Campagnolo Cambio Corsa primitive derailleur -- can it be recreated? Does anyone make this sort of system and sell it today, or is my only option looking for someone selling theirs? I've googled whether similar systems are being made today but found nothing to my liking. Are there any new versions of this?
This system, the Campagnolo Cambio Corsa, or race shifter was introduced in 1946 and superseded in 1949 by the Paris Roubaix which used only one lever, vs. two and again in 1951 by the Gran Sport parallelogram derailleur, which slightly modified is still state of the art. The Cambio Corsa was probably only made for three years. 

It is still possible to buy these parts, complete systems or bikes with these parts on sites like eBay. Keep in mind that the Cambio Corsa and Paris Roubaix systems require special toothed rear dropouts and can't be used on just any bike. 

Even at vintage events like the Eroica it's rare to see them as the gearing is not suited to the routes.