And we found ours, a 91 steel Burley Duet, at Recycled Cycles in Seattle for $350. Considered the S&S coupler thing and decided against it for now. We love ours, have done about 5,000 miles on it in the last couple of years.
Here's a link with a bundle of different tandem articles, links, etc.--
http://www.thetandemlink.com/Learnin...anchor10417632
"My predominant feeling is one of gratitude. I have loved and been loved;I have been given much and I have given something in return...Above all, I have been a sentient being, a thinking animal, on this beautiful planet, and that in itself has been an enormous privilege and an adventure." O. Sacks