It's said you can go all the way up to level fifty regularly, and beyond at a hampered rate... I wonder if someone's trying to get all the skills?
You can try, but you won't succeed. From what I've read, the maximum possible is 100 perks (20 from quests, 80 from levels after having maxed ALL SKILLS to 100), and it's possible it's less than that as I read someone say that while you can level past 50 you don't get more perk points after 50.
Either way, nowhere near the total number of perks available (which is around 200 something).
Regarding my earlier comment on super-fast non-combat leveling, it's easy to level fast that way because it's easy to max out non-combat skills. Just getting to 100 stealth and 100 smithing will put you at 20+ on their own, which unfortunately means you'll be facing level 20+ monster types with minimal combat skills, so be prepared for a rough start. On the other hand, it certainly makes the game a challenge.
The Nightingale armor makes me wish I'd gone with a light armor character. So nice. D:
On the other hand...
...while Dragonbone didn't really impress me (loved the Ebony dark knight look, which is what Lydia's wearing next to me there)...
...Daedric armor looks pretty freaking badass, so it's not all bad.
I do kinda want to reroll with a light armor Nightblade type, but I foresee two major issues with that. One, I'd have to redo all the quests and exploring, which is getting kinda tedious (this would be my fourth character doing the early quest and exploration stuff ~.~). Two, I still haven't found a good balance between physical and magical combat skills because of the limited perks and, more importantly, slow progression when needing to skill up multiple types of combat skills at the same time. Usually one or the other ends up more effective and I use that more, and then the other falls behind to the point of being ignored, and...yeah. That and stealth and magic are completely counter to each other until you get to 50 Illusion for that all-spells-are-silent perk, which seems like it would be absolutely required for any kind of stealth magic-user build to work in this game, which means spamming Calm on people to level up Illusion in addition to the combat skills and...bleh, so much grind. :|
Oh, also, this is what a heavy-armor stealth warrior looks like in action:
Who knew Daedric armor makes you invisible to dragons?