Thanks again for all of the advice everyone was able to give!

Just to update everyone, I ended up getting a RB67 ProS from KEH. Total price around $250 plus shipping. Pro S body, Pro S back and a 90mm lens. It came in yesterday, so I have not run any film through it.

Its huge, unwieldy and completely awesome. Actually, The whole thing assembled (only one lens so far) easily fits in my camera bag, so it will be very easy to carry around. This will by no means be a carry around camera. I can't wait to see what avenues it takes me down.