Mechanical engineering student Kevin Kadooka has managed to frankenstein together two very different Mamiya parts into a custom made camera that combines a twin lens reflex setup with a Polaroid back. He took a Mamiya-Sekor 105mm f/3.5 Chrome from a C-series lens pair, and wanted to give it the ability to shoot Polaroids. Since Mamiya's TLR system didn't allow for Polaroid backs, he created his own, custom camera to do so.
Crafted from laser cut wood, it took him about two months to successfully design. Talking to DIYPhotography, he explained the system:
"Imagine a Rolleiflex, scale it up two times, and add a Polaroid back. Then you have a decent idea of what this camera is like. It makes no claims to the build quality, styling, or ease of use of a Rollei, or even a Yashica TLR, it is a home-grown tool.
The rationale behind this project was that there is no existing camera (as far as I'm aware) that combines the convenience of instant film with the pleasure of TTL viewing (e.g. TLR's and SLR's). While you could easily attach a Polaroid back to an RB67, I wanted to be able to take advantage of the full 3.25x4.25 format.
You can read a description of shooting with the camera in his Flickr stream.
Unfortunately for those of us who want to play with gear like this, Kadooka has no plans to sell a version of this in the immediate future. Maybe we can convince him instead to release the shapefiles for the laser cutting online, so that people can construct their own?