Speaking of bizarre shifting systems, I was a little unhappy to find a set of Campagnolo Cambio Corsa dropouts in a "sold" search on Ebay. Also included the axle, which is a fairly important part. I should set up a search for that so they send me an email. The shifting parts seem to come up more often
Oh, and if you want to go all rando-retro, there are videos on youtube of C.S. Hirose making a Cyclo-style rear derailleur.
https://www.youtube.com/channel/UCjv...kqD1r5g2ISTjeQ