I've recently created the stupidest camera.
120 film, takes 68 format macro shots.
Body and shutter: a box brownie.
Lens: a broken Canon EF 50mm f/1.8. Which isn't a medium format lens. However, the lens is so far from the film that it should mostly cover the medium format frame.
The obvious side effect of this is the changed focal distance: 51.5mm from lens to subject, which cannot be adjusted.
Aperture: fixed and unknown.
Shutter speed: set by the brownie, so only 1/45 ish or Bulb.
In theory this thing should have excellent image quality (the 50 1.8 is surprisingly nice) and be a nightmare to actually use. Note the almost total lack of exposure control, so I will probably only be able to control exposure with flash or filters, or just having the correct lighting to start with.