Mark,
You are correct about the transition from Campy GT to Shimano Crane. At
Schwinn we were constantly working with Campy to come out with an appropriate
touring derailleur. The GT worked fine enough, but when Shimano introduced
the Crane, we switched right away. I got rid of my GT and still have the
Crane.
I don't know when the Campy Rallye came out and I don't think Schwinn ever
used it, except maybe on Paramount tandems later on.
Dave Staub
Orange, Ca