I think Desktop Dungeons should be mentioned here (I think it has not yet been in this thread). Just a roguelike-like, but the dungeons are small, separate blocks there, and you can either lose (which does not advance you in any way, but it also costs almost nothing) or win (which grants you some benefits if you have won in a new way). It also has more calculations, so it should be what punkbohemian likes.
However, I don't like the direction kraflab's ideas and this is going. It is a great feeling to finally win, say, Dungeon Crawl. You look at all your old characters and see how much better player you are now... very satisfying. With dead characters actively helping you, you would just feel that the game has finally let you win instead.
We should also mention two traditional roguelike features which allow you to get something from your old, dead characters. One is the high score list, 100 characters long in most classic roguelikes, so every notable character gets recorded there. Maybe not worth very much, but it does the job, to some extent. The other one is the ghost level: you can find a ghost of a previous character, which is often a good thing (lots of experience for defeating it, sometimes you can find all its equipment).