You know what I think would be a neat job? Going back to some bad old games and reworking them to be awesome. I'd try and keep the same aesthetic, but (depending on the game's problems) refine controls, improve collision detection, obliterate lag, correct glitches, de-blur graphics, expand music loops, replace tracks if they're really bad, improve cameras, add objectives, improve level layout, stuff like that. I'm not talking full on remakes though, more like the same game if they had better designers and technical bugs were ironed out.
Don't know how you'd get paid, most of these would be licensed to some other company, and I don't know how you'd compete with new games, but just as something to study, analyze and improve, I think that would be neat and rewarding.