Since I don't have any myself, I don't want to go buying some if this won't work. I've scrounged around here and the Internet, and can't find if anyone has done this, so it makes me wonder if I should even try. And quick don't-worry--I don't plan on doing this with any high-end vintage frame, probably something fairly low-end, maybe my girlfriend's old 70s Motobecane that's due for a tuneup and upgrade anyway.

I've been reading up on it, but I can't quite figure out if the wheels with, say city/slick tires would fit into an older road frame. My eventual plan would be to make a cushy-riding singlespeed for cruising around town. Sort of a poor-man's 650b conversion. But I'm figuring I'll need to drop the brake shoes 11.5mm in order to hit the new rims. Is that correct? Would I even be able to find brakes with that much distance? (I know Rivendell sells long-reach brakes, but I'm kind of hoping some old centerpulls will do it). I figure I can find some decent, cheap MTB wheels used from someone locally, and I don't have the cash right now to buy 650bs.

Any input, factors I haven't considered?