>>2844178Well the main problem with those slr's is that you'll never get a 35mm lense to reach infinity focus, because the mirror box is in the way.
So while you might be able to get coverage over the entire film area, you'll only be able to focus out to a few inches in front of the camera.
Also, what makes your plan additionally retarded is how cheap mamiya and pentax 645 glass is. Just buy the right gear, dumbass.