At this years Photokina I could have a closer look at the “p-SLR” adapter system made by Sinar.
The adapter system can be used with the Sinar p2 and p3 monorail view cameras and exists in versions for Canon and Nikon DSLRs.
The lens mounted on the camera in these pictures was a 70mm lens and allowed focus-to-infinity.
The official retail price is around 1400 Eur. More information can be found on the SINAR website.