Well, crazy as it is, somebody did it on a Surly 1x1:
http://www.crazyguyonabike.com/doc/?...ed&context=all
http://www.crazyguyonabike.com/doc/?...ed&context=all
If you're going singlespeed, I really do not recommend getting a geared bike and leaving it in one gear. I've tried geared bikes without shifting, and I've tried "pure" single speeds, and there is an enormous difference. I still think it's nuts to tour on a single speed, but I'm not going to dissuade you like everyone else seems to have.