A bit more comprehensive list:
Digidesign SoundReplacer - $395, or free when you purchase the upcoming Music Production Toolkit
Drumagog - $269, Andrew already mentioned it, but it's worth another mention.
apulSoft appTrigga2 - Only $45US but you'll neet the VST-RTAS adapter. I've got this one and it's pretty decent for $45.
and then there is the seemingly perpetual vaporware,
TLLabs Drum Rehab which "will be available soon" (
for the past year or so)