I would definitely like back-up wheels. It'd also be nice to be able to switch back and forth between studded tires and regular tires at the drop of a hat. And since they're custom I know the LBS wouldn't have a loaner pair if I did have a real tacoed-wheel type emergency. It's a really good idea. But right now everything I have, and all I asked Santa for, is an Xtracycle conversion for my old mountain bike. This means I can't even look at the stuff on TE, not even the stuff on sale. "Xtracycle!" I keep reminding myself.