Quote Originally Posted by StoneNYC View Post
If you could create a petzval that worked for 4x5 AND had a shutter, this would be of much more interest to me sadly.

Actually, the Mamiya RZ's lens shutter works independently from the other electronics, it's possible you could set a simple function to simply trip the mirror lock up, and leave the rest of the functions to the lens as normal, if it had it's own shutter.

(And the Hassleblad C's as well)
Yes, technically it is not very difficult to calculate the lens that will work with Mamiya RZ or 4x5 cameras, but building the prototype is really expensive. And the only thing that can compensate for expenses is the volume of production. Especially when it involves fairly complicated shutters.
I seriously doubt that the effort will be paid off.