I've had this concept in my head for some time now but since in my tablegroup I'm the DM, I really haven't had a chance to try it out:
A halfling (or possibly a gnome) Druid/Sorcerer/Mystic Theurge who is quite insane, hearing voices in his mind (possibly even having hallucinations, if you're up to it) and having delusions of grandeur (of which I'm happy to tell you more about privately). He comes from a faraway land, a big city near a great sand desert and has been exiled for crimes he doesn't speak about.
So what do you think?
Oh, and I suppose I'd better mention that I've never played a pbp before so if you have a problem with that let me know. But with over ten years gaming around the table, I think I can get the hang of it pretty fast.