I would find this data interesting. In addition to baselength, the magnification factor of the VF would be needed as well. It would be difficult to find many fixed lens rf's that didn't meet focusing criteria as measured by the calculations used in the thread for removable lens rf's.
It's interesting to note that Minolta offered up it's 90/4 Rokkor with the very short baselength CL which close up and wide open should not-focusable or a significant focusing challenge, yet some users go to 2.8/90s, and others have issues wtih 40/1.4 and 40/2 which the current calculations show should be easier to focus than 90/4.
My personal experience with the Canonet, XA, and GSN is that the focusing patch is relatively small to most LTM or M mount bodies, so independent of baselength, that is an issue for focusing these fixed lens RF's.