Why hello there, i'm the one who immediately suggested we do this. -Modelwalks-
Obviously, i'm interested, and i have LOTS of ideas on how to run this stuff. :3
Much like a lot of the novels do, the way it works normally works is the prospective planeswalkers travel around and gain ahold of areas of land that have strong mana, as well as somehow attaining creatures and developing spells to use, sometimes copying them from others.
The way I think works best is that each Planeswalker has their own little demiplane, probably linked to some nifty item they have on their person. In order to acquire artifacts/creatures/etc they put their personal magic 'touch' onto them, like a mark or something . . maybe work out deals or force the creatures into submission. Let's say this allows the creatures to go on with their lives, but it saves a 'copy' of their current power/mental state/whatever in that demiplane that the Planeswalker can call on.
As for mana, the Planeswalker puts his mark into a special place with strong mana, creating a link between the place and himself, so he can call upon it's mana in the future.
On the Planeswalker's person, he keeps a token of some kind that acts as a link to whatever essences he has in his demiplane, allowing him to easily summon it by using the right amount of mana. You use the token by thumbing it, kissing it, brandishing it, whatever to help you summon your whatever.
When the creature is killed, the token burns up, probably necessitating you to find that creature again and re-make a contract . . if they let you. Maybe when a creature you summon dies, the original weakens or something somehow, to give less incentive for certain creatures to want to ally with you?
Magic spells are developed by the mage himself, and can be re-developed and 'readied for use' if countered/used up/etc. Artifacts . . well, if you have the real artifact, then you can keep making essences or whatever of it if your essence of the artifact in question ends up destroyed somehow.
Rather than suffering wounds, Life can be displayed by your spiritual resilience or something. Probably personalized for each person. Your total Life is represented by how many nifty floating magic barriers/etc you have protecting you. When you run out, you give up, because dying SUCKS. Rather than being brought to negative somehow (NO LICH SHENANIGANS!
) maybe your last shield soaks all of the overwash damage and leaves you helpless?
As for rules, the game should be played with standard rules except for the changes as outlined above, but you can essentially 'draw' any card from your deck at any time. Normally 1 mana played per turn, start at 20 life, etc.
Using the Banlist is fine by me, and picking what format (Classic/Legacy/whatever) would be a good idea. Also, we should pick a limit to what amount of mana we have in our deck. Maybe also limit how many Colors we can use to start? And yes. Deck Lists are good.
Edit while Posting: Hmm, picking a limited amount of Sets for each character to choose from would be a neat concept. Maybe one person picks Urza Saga, one Rath Cycle, etc? And yes, also we should have Limit Etc of a card per deck like usual. Maybe the nature of the magic makes it naturally more like the Trading Card Game?
Also, MSN or AIM or SKype or something chat would be handy, no?
BIG EDIT: OOOH! Maybe when you win and have your . . fun . . you also get the ability to use one Set of the loser's chosen Block? Would be a neat competition-inspiring rule.