The Panasonic GF1 with the EL-Nikkor 50mm f/2.8 mounted in its focusing helicoid. This camera has been modified to have M42 mount so allows easy experimentation with various "exotic" lenses. In the case with the EL-Nikkor, I assume even a standard M4/3 camera could have had sufficient register distance to allow mounting the enlarger lens and provide infinity focus. At least the 63mm f/3.5 and 80mm f/5.6 EL-Nikkors would do this on my other GF1/GH2 Panasonics, or even F-mount cameras. (tested: yes, this works also with the non-modified bodies)
The focusing helicoid used here is 15-27mm. The more ubiquitous 17-35mm helicoids are too long for infinity focus.