This is what I'm talking about. The tools for what you are trying to put together already exist in forms that are readily available and made to work in the way you describe.
What you currently have:
- RB67 back that needs a P adapter or G adapter... can't remember which.
- Some method to focus on a ground glass. The RB back adapters were not meant to work this way.
- A lens that has the shutter cocked internally and by a screw drive. And with a lens mount adapter in place, inaccessible by any tool with which to cock it.
See where I'm going?
Hasselblad, Horseman, Linhof, Mamiya (did the Super 23 have a tilting back?), Rollei, Graflex (and probably others) all made medium format roll film cameras with movements.
One thing that would make your original idea more plausible would be to use a lens in shutter instead of the V mount 80mm.