Good luck with the bellows.

Of course most any 4x5" camera can take rollfilm backs, and there are dedicated rollfilm view cameras, so they can have more movement than the Bronica bellows. There are also the Hasselblad Flexbody and Arcbody. I think the ultimate would be the Linhof M679.

But for the price, and the potential attraction of having an SLR with movements (the downsides being mirror slap and shutter vibration), it's hard to do better than the Bronica. You can even adapt LF lenses to the screw mount.