I designed a roleplaying game for Dungeon Keeper. It's not strictly Dungeon Keeper, but most everything you can do in that game you can do in this one. It takes place on a wiki and a google doc, so it's closer to a tabletop game than a videogame. If you want to check out the game, visit: http://dungeonoverlords.wikispaces.com.
You can play as an archon, which is my term for a dungeon keeper. Good or evil, allied with the underworld, or the overworld, or both, or neither. You can have just about anything as a minion. You can customize your rooms with traps, chests, and just about anything imaginable. It's part city-building game, part wargame, part roleplaying game.
Alternatively, you can play as a champion, the equivalent of a lord of the land or horned reaper. Serve other keepers, or raid their dungeons. Hire yourself out as a mercenary, or fight for higher causes.