The single speeds we had as kids weren't
quite as nice as the ones around now, but one thing for sure is I never got off the fat tire thing!
But I understand your point - there's not a hell of a lot to be said for singlespeeding, unless you are just really pissed off at your shifters and drivetrain combination. It's metaphysical, I think. Now fixed gear is something else, and there are people who take those things off road. THAT's fringe.
http://www.63xc.com/