Careful what you pick up on ebay for rearsets if they're from China. I've heard a bunch of stories about people buying them, then finding out they're complete crap. Very thin metal, they break, the bolts are too short and immediately rust, etc.
MotoCarrera used to make a really nice set for the Yamaha RDs. You can adapt a bracket pretty easily for any old steel tube bike to make them work. Dunno if they're selling them anymore since the owner is almost dead (if he isn't already).