There are "lens Hackers" out there that adapt lenses from fixed-lens rangefinder cameras to Mirrorless and interchangeable-lens rangefinder cameras. Some as a Kitchen table hobby, and others like japan-exposures, for a small business.
Flickr has some threads where members have adapted the lens from a Yashica GSN to mu-43 mount.
The half-frame lenses are very compact. The F1.9 aperture is enticing for that lens. It would be easier to adapt an Industar-69 28/2.8 (Chaika half-frame) or Robot 30/3.5 Schneider. The I-69 can be used with a 39mm Leica mount adapter, but the mount or lens has to be modified for infinity focus. It needs to be moved in 1mm. The Schneider lens is nice, but 2-stops slower.
Yes. I´ve seen this lens mounted on a NEX but then I lost the link. I´ve just found it and realized the guys had to tear the camera apart and make a DIY job to get it to fit on the NEX too bad. It would have made a perfect pancake for the nex.
Yes, Selenium metering. You would be amazed at how long Selenium meters can hold their accuracy. I have a Weston 615 from the 1940s that is still perfectly accurate. I use it with many of my manual exposure cameras. Had it out today.
with these cameras- hard to tell until you start taking it apart. One possible arrangement suitable for easy lens hacking is for the lens to come out as a complete unit, such as the Olympus RC and ECR. The Shutter and aperture is behind the optics. So, in that case- the selenium cell would not transition unless you just wanted cosmetics. Just put the optics module in a suitable helical. The 28mm F3.5 comes out of a Nikon lite-touch as a single-piece. Transplant it into an Industar-69 helical, get a full-frame 28mm lens in Leica mount. With a lot of "between lens shutter" cameras, like the Minolta hi-matics, yashics GSN, and others: you need to take out the shutter leaves, or lock them into the open position.