Let me think. I've suggested a few to my hubby, but I'm not sure if he'll ever do them. There's also a few he's thought of but hasn't done yet.
Hasn't done yet: The Dude (from the dream sequence), Wash, Connor MacManus
Suggested: Shigure, Kenshin
He doesn't do costumes all that often, especially if I suggest them.
Which gets a little annoying after a while.