I bought a Thule Roof box - doesn't kill gas miles and I can get more than 6 pairs of wheels in it, along with a ton of other stuff -
flips open on both sides of car - pretty handy.
Came in handy for trips to NUE races as well.
Yeah, I couldn't find those on the TCB site, either. I think you can get away with two tarp bungies (the kind with the loop of bungie and an orange rubber ball used for event tents) on the handle bars and a third at the base of your fork around a spoke or two to keep it from rattling...if that doesn't work I'm going to fashion something rigid to attach to the fender eyelets on my bike. Looks cool for getting across town to the local training course for practice while saving some tread.
Thanks, Brendan. I think you can just email Tad Bamford of TCB to find out about them. Also I see in the comments section on Bike Portland.com that someone else posted a DIY version, using toe straps and some sort of attachment to the front anxle. Some info here, but not much: