If anyone goes to NAHBS, please let Ritchey know that it would be really cool to see a coupled tandem design that allowed configuration either as a tandem or as a single, by mating the captain's top tube and down tube with the stoker's rear end (seat tube, BB, seat and chain stays).

If the tandem was approximately the same size front and rear, it seems like Ritchey's coupler design could support this, with some mods like a dummy down tube on the stoker's BB. I think this would be the ultimate travel bike, since it could support either single or tandem use.