Lol, you have some issues!
It's... possible. With some face paint and a pair of stilts.
Hm... i'm not too sure about that. I guess it depends on if you want the creepy serious kind of Joker, or the more fun Mark Hamill kind of Joker?
@joygirl: Interesting, he definitely could do wacky insane well... and I bet he could do sinister... and maybe even threatening. I think his interpretation of the Joker would be fun to watch, but it'll never happen.
Who would be the Batman to his Joker? Can I suggest Bill Hader?