Back in the late 1980's we sold a Rodriguez aluminum tandem that was made for us by American Mfg. It was called the Rodriguez AL26. The tandems were beautiful polished (or brushed) aluminum and incorporated a replaceable tab on the rear drop out for mounting the derailleur on (the same one that American used on their aluminum bikes). A problem arose several years ago when the replaceable part became 'no longer available'. I originally had an emergency batch of them made by a machine shop in Oregon, but we ran out of those, and then that machine shop went out of business.
I always wanted to update and improve the design of this part anyway. It was originally machined with pretty loose tolerances, and bent easier than it should. The derailleur was too low, and too far forward so it was difficult to remove and reinstall the wheel with the skewer in the hub. As people brought in these old bikes to upgrade them to modern shifting, the derailleur was too far forward to shift well.
Well, our machine shop is running so smoothly this year that I decided that we should try and make a batch ourselves. I located someone who had one of the tandems in question, and borrowed it for a while. We now have an improved model of this part in stock for those of you who have one of these tandems (or an old American Mfg. bike). This one is lighter weight, and addresses the shifting issue as well as the wheel removal issue.