Here are few I just came up with, and a couple that I just really like:
JT "what, are you waiting for it to" Snow "in SF before you score?" (2003:
Mark "thrown-out-from-right-field!" Portugal
Ruben "the biggest idiot in the world other than Rico" Rivera - this one isnt clever, but its so true it hurts
Neifi "why are you in the majors?" Perez
Ivan "Pudge" Rodriguez - this one's just really cool, IMO
George "douche-bag" Steinbrenner - this is coming from a Yankees fan, too.
Nomar "schizo" Garciaparra, aka "Tic, tic, tic, swing"