Well perhaps I should clarify that the $100 is not FIRM, per se. I mainly just wanted to get the conversation rolling, which it certainly has! I've been contacted by a friendly user & thanks to his suggestion I'm looking mainly at the Mamiya 645s. I just saw one w/ 2 finders and the 80mm f/1.9 go for $168 on eBay! Sounds pretty darn good.
Here is my newest question though... why do the C330s and C220s, etc, go for so much more than the 645s? It seems to me that the SLR would be more desirable, no? Perhaps it's the close focus, leaf shutter, etc.
Thanks again to all who've replied!