I really want to thank everyone for helping me walk through this. I hadn't considered the "heft" of a RB, although I heard its a beastly camera. In a perfect world, I'd love to have a decent studio setup with this camera. While thats probably not going to happen immediately, I should probably rethink a little.

Motivations behind looking at this camera were:
-larger negative size (currently only shoot 35mm). I consistently enlarge to 8X10 and I thought a 6X7 negative would be ideal. I'd also like to start going even larger as well.
-rotating back a plus
-120 film backs - Having been stuck with a roll of 36 exposure film in my 35mm cameras, I'd really like a MF system of some sort that accommodates interchangeable backs. I shoot mostly HP5+, but I like using 100 ISO film for landscape and outdoor. 35mm cameras are much more compact, but all that compactness goes out the window when you start having to carry multiple bodies and lenses!

While I don't plan on hiking the Appalachian Trail with this or any other MF camera, the ability to take it out and hand hold every once and a while would probably be good.

With that said, can any one suggest a MF camera that fits decently within these specs (negative ratio is probably the least concern)?