I have access to a toolroom, with a Hardinge lathe and a Moore jigborer, so I can machine whatever I need, to whatever tolerance is appropriate, with the exception (for now) of metric threads - there are some ways around that, though. It looks like the focussing mount (inner helicoid) from a late J-8 can be bored out to accept the optical cell of a H-103. I like the Helios because it's a typical clinical-looking double Gauss, just like my 50/2 Nikkor H's.
As for the collapsibel I-61, it may be possible to remachine the I-10/22/50 focussing mount and fabricate a new barrel to accept a (possibly remachined) optics cell from the I-61. I'll most likely end up with examples of these lenses anyway as users, once I do five minutes with a dial caliper will tell me what's possible... maybe a collapsible H-103!
The there are all those M42 Soviet lenses...
For what it's worth - http://forum.mflenses.com/helios-103...on-t53684.html