Take a look at the Bilenky website - they do a lot of retro-fit SS couplers on steel tandems, I have a quote for such right now on one of my bikes - Gary Bushnell may as well. I understand a retro-fit on a alum frame is not practical. So you could shop for a awesome deal on a steel tandem take it on a trip and see if that works and if not have is cut up when you get home. (TG), is right though, there are on a occation awesome deals on coupled bikes that come up - but not as often as a straight un-coupled tandems. So patience can work to your advantage - By the way the best deals I have seen on new coupled tandems was recently at R&E Cycles in Seattle for several their Rodrigez tandems.