My Busch Pressman C has a 620 Adapt-a-Roll that will do 120 film at both 6x9 and 6x7 with a mask. I see reason you couldn't also make and easy mask for 6x6, and 6x4.5 for it as well. And since you just turn the dial on the film back to the next marker to advance the film, you could also make your own supplemental dial mask for those other formats. It would also be easy enough to adapt 135 film for it for panoramic use. Really, you could do that same thing with a lot of cameras that don't have the film back directly integrated into the camera body.
The problem with any camera that does all of those different formats is that they're not going to be able to keep track of how far to advance the film if you try to switch formats mid roll. So once you've started a roll at one format, it's best to use that format for the entire roll. That doesn't make them super versatile. However, if you shoot at your largest desirable film format (6x7 in your case) you can always crop the images down afterwards to all of the other formats. You'll waste a small amount of film doing that, but it'll be a lot more convenient.