Ok - since you probably asked at least one of the following (reasonable) questions when reading the title -"why the hell would someone want to do that, doesn't this guy know peel-apart Polaroid film is dead?" or "does this guy know there's a native RZ67 Polaroid back?" let me address them both. Yes, and yes. As to why - read on!
I have been ̶h̶o̶a̶r̶d̶i̶n̶g̶ stockpiling discontinued Polaroid film types for about 12 or so years now. One lesser-known type which Polaroid produced in its twilight years is Polaroid Type 80, a square variant of the rectangular type 100 peel apart (a la FP-100c). Type 80 was an oddball film in that it was aimed at both the most casual of consumers (the only native Type 80 cameras which Polaroid produced were very rudimentary hardbody plastic, single shutter speed toy cameras) - but also at photography pros, for use in proofing backs (Hassleblad made a Type 80 back for the 500c and Mamiya made one for the RB67 - the image area of the film is roughly 6x6). Type 80 was killed off a few years before the mass extinction event of Polaroid film in 2008, and is fairly difficult to find these days. I've been saving every pack I buy for eventual usage in one of the more versatile professional options.
About 2 months ago, I finally pulled the trigger on an RB67 Professional that I found local to me for very cheap ($200). I primarily bought this for the sole intention of using my Type 80 film in. The 50mm lens is in good shape but the body and 120 back are both a bit rough, and of course it's the oldest model out there. I've been considering detaching the lens and selling the rest of the rig for parts, and in turn buying a Pro S or SD. Today, however, an RZ67 in very good shape popped up - the camera, Z series lens, 2x backs, WLF, the metered prism finder, and a pelican case, all for a very reasonable price.
I was ready to pounce on it when I realized this (admittedly very stupid) problem - Mamiya did not make a Type 80 Polaroid back for the RZ67, only a Type 100 one. The only Polaroid Type 80 back is the Mamiya M80 (+P Adapter), which is only usable on the RB67 platform. While I would definitely shoot roll film in the camera as well, as mentioned above my primary motivator for getting an RB/RZ is definitely using my Type 80.
So - my insane question is this: Would it be hypothetically possible to use one of the RZ67 Polaroid backs to modify the Mamiya M80 Polaroid back?
Thanks in advance for indulging me.