I've got an old zeiss ikon folder I might have to try this with. Maybe pick up an older digital body to toy around with. I did some quick testing and was able to get an image to appear on my rear LCD of my XPRO2. The trick, is getting things attached together and light tight around the rear.
Also, the Zeiss I have does not allow for the back to be removed. It is permanently attached with a piano hinge. It does open flat, so no big deal.
My attachment thoughts are to see if I can find some way of attaching the camera using the 120 film wheels...perhaps attaching the metal spools to a plate of some kind and then attaching the plate to the cameras tripod socket, then attaching them both together with another plate to the tripod socket.