A good number of people like their coupled bicycles and we also build and retrofit a lot of bikes with S&S couplers which do tend to add a lot to the cost of a finished frame.

We have one expedition tandem that can also be a triplet, single long tail tourer, and has a kid along attachment which is all made possible because of S&S couplers... and it sees a lot of use in many ways. It belongs to a friend who will ride to the coast with his wife in a tandem mode and when he arrives there, meets up with the single rear section (which he ships ahead) so he can ride back solo while his wife does business there or returns by plane.

More people are using folders for touring and Bike Friday probably has done the best job in building a tour worthy folder that excels in the ride quality department... am seeing more and more people going this route.

Most of my long distance riding is done on a folder which is a highly modified Phillip's 20... I built around the base H frame to retain the excellent hinge assembly which also allows the bike to be separated and packed in a much smaller and airline friendly package.

From this I will probably build a one off incorporating a similar hinge for folding and S&S couplers for more compact packing for travel... because I can do this kind of work and enjoy the challenges of design and building and stepping outside the box.