Henry Tillman beat Mike Tyson twice in the amateurs, when they met in the pros Tillman lasted about 2 minutes.

Forrest beat Mosley in the 1992 Olympics trials i believe, in the pros Forrest beat Mosley twice.

Taylor beat Pavlik in the amateurs, everyone knows what happened when they met as pros.

Greg Page beat Tony Tubbs 5 times in the amateurs i think, when they met in the pros Tubbs won a 15 round decision.

Jorge Luis Gonzalez beat Bowe in the amateurs, when they met as pro's Bowe KO him in 6.

I'll think of some more later.