polygot, I think Bermpohl utilizes a slightly "crooked" design like you're referring to. http://www.vintagephoto.tv/bermpohl_img.shtml Would you agree?
Steve, thanks for your offer of assistance. I think we're a long ways from actually doing anything, but this kind of group effort is just the type of thing that could make this project a reality someday.
Michael, I hadn't thought of that... does that mean in the typical arrangement, 2 of the images will actually not be mirrored, and the remaining plate, being struck by the % of light that was never reflected, only transmitted, would give a typical mirror image negative? I guess so..
If we pretend filter factors are all equal, then a 33/66 mirror at the front, followed by a 50/50 mirror would give equal exposures on all plates. 33% to the red (in the case of the Curtis above), and the remaining 66% split down the middle to green & blue. However, there might be a more novel arrangement if we consider filter factors.