Found this one on eBay, and couldn't help but note that it looked like Rally 3rd gen, not Euclid:
Contacted the seller regarding the matter, and he gave this reasonably convincing story regarding them:
Now, I'm not directly doubting him - just curious for a second opinion on the subject, and to see if anyone else has heard of Campag using the 3rd-gen Rally design with Euclid. Seems just a tad odd that I haven't heard about Campagnolo being this inparticular about parts though.Sorry to say, your catalog may state this derailleur as being 3rd generation Rally, but we know other. We purchased 40 plus complete Euclid groupsets from a Norweigen dealer.........And on his paperwork direct from Campagnolo it states other.....50 X Capmagnolo Euclid groupsets......So to say, not a Rally.........It's called relabeling. When Campagnolo Record groupset changes over to Carbon.....The old Record then......Became Chours. I've been dealing with Campagnolo for well over 35 years....And I don't depend on their catalogs all of the time.....For years and years I have done business with 2 of the biggest Western European Campagnolo suppliers. So big they would have 3 to 4 40ft truckloads of Campagnolo parked in the parking lot...So to say I'm pretty much informed of all of the offering, first hand. I've seen stuff that no other has seen, like team production items.....Early Victory brake levers were really SUPER RECORD....Early Victory headsets were NUOVO RECORD. Later Victory Lisure front derailleurs became early Euclid front derailleurs as like later Victory triple canksets became early Euclid cranksets.........Well I guess you can say this derailleur at one time may have been a RALLY..............Now Euclid.
Incedentally, I like the idea of a Rally-looking derailer on an MTB. Sharp.