I'm going to be hacking in a magic system which gives the spellcasting classes the power to cast 4th-9th level spells. (although you have to go through a lot of effort to do so, such as going to the top of a mountain and arranging 13 virgins in a circle so that they can sing a song under the new moon which breaks any enchantment.)
I'll go ahead and post my E6 Variant rules, starting with the demographics manifesto.
In the World of Eberron, one in a thousand people are members of the PC classes. For every character of 6th level, there are 60,000 mundane individuals. Given that 6th level heroes tend to cluster in larger cities, this means that most people will never even see someone of this level. (in fact, many will never see a member of the PC classes) but they will certainly hear of them.
On the entire continent of Khorvaire, with it's 15 million people, there are about 250 true level 6 heroes among the common races, out of 15,000 members of the PC classes. NPC classes speak for 50,000 additional level 6 characters, 35,000 of which are 6th level commoners. What is a 6th level commoner? A 6th level commoner is a pillar of the community, someone who can create a masterwork, run a business like a master, and quite often knows more than many wizards. 7,000 of the level 6 NPCs are warriors, quite often generals and members of special forces units at this level. Such people are often equipped with magical weapons and armor, and their exploits are spoken of in song.
Another 5,000 of the elite NPCs are experts, the absolute greatest craftspeople, scholars, and musicians in the world. These people are extremely well known national treasures, doubtless quite famous, at least in their home region. Khorvaire has about 1,500 level 6 magewrights, who do the practical work of creating many of the magical wonders seen across the continent. The contributions of magewrights are valued everywhere, even if their works pale in comparison to that of artificers. Across the continent, there are 750 6th level aristocrats, many of which are in line to take control of an entire nation. They are master negotiators, some of the wealthiest and best educated in the world. Finally, about 750 6th level adepts perform the most powerful magic most people will ever see, shocking and amazing with their incredible, world shaking might.
Perhaps a tenth of 6th level members of the NPC classes might have one or two levels in a PC class. This is extremely remarkable, however, and something that will truly define a person. Monstrous humanoids of various sorts have a natural advantage in toughness and power, and about 30,000 equivelent to a level 6 character live on the continent.
Merely being a level two character is quite special. Two thirds of the population never acheives this level of ability, although in many cases it simply represents an upwelling of talent. Level three is where a person defines themself. A level three individual now has another feat, and is simply noticably stronger than nearly anyone else. Level four individuals are frighteningly remarkable, the kind of master that an average person may never forget meeting. The deeds of a level five character may very well need to be recorded in the history books somewhere. Such people are one in a hundred, and live remarkable lives.
As sixth level PCs, your characters are among the strongest people in the world, and likely have an amazing reputation. Acheiving sixth level can take a lifetime, or it can be foisted on a character in a flurry of adventuring experience. The only common thing between 6th level characters is their undisputable status as heroes.
This game uses the E6 rule, where character have a level cap of 6, and then gain feats for each 5,000xp gained afterwards. Characters for this game will start with 26,000 xp, meaning that they are 6th level characters with one additional feat. Abilities are to be generated using 42 point buy, and races of up to LA +5 may be selected in exchange for using a lower point buy. (instead of the level adjustment. Racial hit dice count against your PC class levels, but monster classes from Savage Species and Libris Mortis may be used.) A base stat of 19 may be purchased for 20 ability points, and a base stat of 20 may be purchase for 24 ability points.
LA +1: 35 point buy
LA +2: 28 point buy
LA +3: 20 point buy
LA +4: 10 point buy
LA +5: 0 point buy
Characters receive 1/2 maximum hit points on each hit die roll, save for the 1st level hit die roll, on which they receive the maximum possible as normal. Characters receive a starting wealth of 15,000 gp. This wealth may be increased by trading starting xp for wealth at a 1:3 ratio, meaning each sacrificed experience point grants 3 gp. A character wishing to start with additional experience may sacrifice starting gold for xp. A character may also take NPC classes instead of PC classes, in exchange for 2,500 gp or xp for each NPC class level taken. NPC class xp bonuses may not be traded for xp. The spellcraft skill is considered a class skill for all classes, and used to cast ritual magic.
Characters start each day with two action points, and gain an additional one at the end of each encounter. The action point total resets to 0 when the character rests. Most feats and abilities that increase the number of action points a character has give the character one additional action point per day, and an additional action point after every 4th encounter.
Material may be selected from any of the following books, but all non core material must note its source, with page number reference:
All three core rulebooks
Complete Arcane
Complete Champion
Complete Warrior
Complete Divine
Complete Scoundrel
Complete Adventurer
Complete Mage
Eberron Campaign Setting
Magic of Eberron
Faiths of Eberron
Dragons of Eberron
Sharn: City of Towers
Five Nations
Explorer's Handbook
Secrets of Xen'drik
Spell Compendium
Dragon Magic
Tome of Magic
Tome of Battle: The Book of Nine Swords
Psionics Handbook
Complete Psionic
Book of Exalted Deeds
Book of Vile Darkness
Frostburn
Stormwrack
Cityscape
Dungeonscape
Player's Handbook 2
Magic Item Compendium
Savage Species
Heroes of Battle
Book of Aberrations
Book of Erotic Fantasy
Netbook of Unlawful Carnal Knowledge
Portable Hole Full of Beer
In addition to the material listed above, players may also select from the following feats:
Ability Training (General)
Benefit: Choose one Ability; You gain a +2 bonus whenever you are making an Ability Check with that ability. This bonus does count when making a skill check using that ability, but not for any other use of that ability, such as spells per day, or hit points per level.
Special: You can gain this feat multiple times, its effects do not stack. Each time you take this feat it applies to another ability.
Ability Advancement (General)
Prerequisite: Ability Training in the same ability.
Benefit: Choose one Ability. You gain a permanent +2 bonus to that ability.
Special: You can gain this feat multiple times, its effects do not stack. Each time you take this feat it applies to another ability.
Capstone Training (General)
Prerequisite: 6th level
Benefit: Choose one class feature you would gain if your level in a given class were two higher. You gain that class feature, and qualify as a member of that class two levels higher than your current level for the purposes of qualifying for feats.
Special: You can gain this feat multiple times, its effects do not stack. Each time you take this feat it applies to another class feature. You may select a class feature from a prestige class, including one you have gained a class feature from via prestiege training.
Class Training (General)
Prerequisite: 6th level
Benefit: Choose one of your class features that improves as you increase in level. That class feature improves as if you had gained levels neccesary to improve it, for example increased sneak attack damage, bonus feats, or acquiring improved evasion. Iterative class features which increase every level are considered to improve as if you gained two levels. This feat cannot enhance spellcasting in any way, save for spell like abilities gained as class features.
Special: You can gain this feat multiple times, its effects do not stack. Each time you take this feat it applies to another class feature. Class features gained through capstone training and prestiege training may be chosen for this feat.
Expanded Spell Knowledge [General]
Benefit: You learn 1 or more new spells known, with spell levels totalling to half of your caster level (round down, and treat a new 0th-level slot as 1/2). Thus, a sixth level Sorcerer could gain one 3rd level spell known, one 1st and one 2nd level spell, three 1st level spells, or 6 0th-level spells. This feat cannot provide spells known of a level higher than you can already cast.
Special: You may take this feat multiple times; each time you take it it provides
more slots.
Expanded Caster Stamina [General]
Prerequisite: Character Level 6th
Benefit: You gain 1 or more new spell slots, with spell levels totalling to half
of your caster level. Treat 0th level spells as 1⁄2. Thus, a sixth level Wizard could gain one 3rd level slot, one 1st and one 2nd level slot, three 1st level slots, or 6 0th-level slots. This feat cannot provide spell slots higher than you can already cast.
Special: You may take this feat multiple times; each time you take it it provides
more slots.
Metamagic Mastery (Metamagic)
Prerequisite: Metamagic feats (see below), Caster Level 6
Benefit: When you take this feat, select a metamagic feat. You must have a number of Metamagic Mastery feats equal to one less than the level increase of your chosen metamagic, to apply this feat to a metamagic feat. For example, Empower Spell, which boosts the level of a spell by 2, has a prerequisite of 1 Metamagic Mastery feat. Split Ray, which has an increase of 1, would have no prerequisites. As a swift action once per day, you may apply this metamagic feat to a spell you cast with no adjustment to the level of the spell cast, or increase in casting time; for a spontaneous spellcaster.
Special: This feat may be taken multiple times, its effects stack.
Prestige Training (General)
Prerequisite: 6th level
Benefit: Choose a prestige class you could qualify for by 9th level. All special requirements for the class must already be met. You gain a class feature that presige class gets at 1st level. For the purposes of the capstone training and the ultimate mastery feats, you are considered to be level 1 in the selected prestige class.
Special: You can gain this feat multiple times, its effects do not stack. Each time you take this feat it applies to another class feature. You may only take this feat if you could qualify for the prestige classes you have abilities from simultaneously.
Ritual Knowledge (General)
Benefit: Your gain permanent knowledge of a number of levels of rituals equal to your level + your intellegence modifier. Permenantly known rituals may be cast without need for a ritual schema.
Special: You can gain this feat multiple times, its effects stack, though their effects do not increase retroactively if your intelligence or level increases.
Skill Savant (General)
Prerequisite: Skill focus in selected skill
Benefit: You gain a +2 untyped bonus to the skill you qualify for use with this feat.
Special: You can gain this feat multiple times, its effects can be stacked a number of times equal to the ability modifier of the relevant ability for the skill. The feat can also be taken and applied to different skills.
Ultimate Mastery [General]
Prerequisite: Capstone Training
Benefit: Choose one class feature you would gain if your level in a given class were up to four levels higher. You gain that class feature. You may select a class granted by a prestige class you have gained a feature from via prestige training.
Wondrous Rings (General)
Prerequisites: 6th level, Craft Wondrous Item
Benefit: You treat rings as wondrous items for the purpose of meeting item creation prerequisites. You must still meet caster level requirements for any ring you create.
Retraining:
Instead of gaining a new feat when a character's experience total is high enough, the character may choose to "retrain" on of his or her previous levels into a level of another class. This may be done with levels in monster hit dice, as well as with normal classes. The highest hit die and skill points between the two classes are used, while all other class features change to that of the new class. The original class assignment should be noted on the character sheet. The character may not reassign spent skill points, but may assign new skill points gained by switching to a class with a higher number of skill points freely as a typical multiclass character.
A character may switch levels between retrained classes by spending 1,000 xp and spending a day practicing and excercising to adopt different skills. The highest level of a class is always retrained first, and a character may not use feats or spells he no longer qualifies for.