Upload & Sell: Off
Probably the most versatile SB unit would be the already released Alpa version if there were more adapters available. You can find them now for Nikon, M42 or Leica-R lenses, but it's old stock, demanding silly high prices, due to the collector's value.
In theory, it would be possible to make Alpa adapters not only for the lenses above mentioned but also for Minolta MD, Olympus OM, C/Y and Canon EOS. Not for Canon FD glass, I guess.
Of course, there isn't modern production of any kind for adapting other lenses to Alpa SLR cameras ( discontinued for more than 30 years). Let's see if some Chinese 'entrepreneur' takes the risk. My bet is that nobody will; this is a too small niche market.