As Ntenny correctly surmised, the frame is indeed in two pieces, the solder/rivets having separated. The ground glass is 'free' in the sense that it isn't there at all...

I've been asking around if anyone has any of these to give away / sell as a parts camera, but so far nothing.

My girlfriend is a goldsmith, and quite an accomplished metalworker, so I'll see if we can figure something out.

We're also, once I have a replacement shutter, going to have a look at repairing the original shutter's innards, perhaps even improving it, and we'll be documenting the process.

But yeah: a Skopar-equipped junker with a working shutter would be the solution to the front half of my worries...