I've actually been a player in a couple of campaigns themed like this. first example, we had been getting stagnant as a gaming group, just playing retreads of a few old characters ittermittently and we finally just decided to bring the characters back, the dm agreed. there had been a reall strange accident in my wizard's lab at level 9 so that was our starting point, all the characters had been there so it worked, we played the characters from that day on. two paladins and my cn pyromaniac mage. in the cataclysmic battle described at the beginning of the next one, all the gods of the world had perished in a struggle against some freakishly powerful entities so the pantheon needet filling out. all three characters became gods. one was a law, justice, tyrish type, one a diety of order, protection and the slaying of unnatural beasts (undead, lycanthropes, demons ect...) and finally, my boy, the chaotic evil god of destruction, rage and hatred. a lifetime of constantly being preached at and told how terrible he was despite his equal effort and sacrafice had darkened the soul of my mad wizard, one magic item of undetectable alignment later they had no idea and probably would have killed anyone who had the audacity to accuse my little man of anything, he had a higher charisma then either of the others and made great efforts to keep them appeased. the fact that i remember it leads me to believe that it worked swimmingly.
the other time i tried it, my level 18 2e character with three classes, translated roughly into a level 27 3e character by the wotc conversion doccument, oh look, the guy i started at lev 1 and played to 18 is not playable in the campaign anymore. he becomes a diety in a solo game and sacrafices himself and the entire pantheon to stop a war among dragon's, men who had learned to absorb the souls of dragons and the gods themselves that he believed would destroy the world. later, the dm decided to bring the gods back as mortals (i also got to play bane at one point woo hoo. undead armies don't backtalk and you only need clerics to keep them in line, once you regain enough power to have them, the world falls in line pretty quickly if you can dig up enough bodies) from their purgatory and i got to play my character again starting at level one. he had only vague recollections of his former life, barely even remembering his own name, remnembering only that he was a bard (2e blade) and favored mithral great swords, two of them. monkey grip is a great feat for flash over substance fighting. i regained godhood, though in a much less cool fasion. going from protector of the universe to strategy, leadership and cunning is a bit of a step down but hey, i took what was there and fit.