Sometimes, just sometimes, people share useful links in the comments section of the entries here. Yadar linked to this video in the less-than-practical Tricks of the Trade: Episode 1 edit and man, it makes total sense. Well, at least for a big bike. Not sure if it’d work on a road bike or a track / fixed gear. Who wants to try it out and report back? I guess you’ll need a knife, unless you’ve got a disk brake. Very similar to those $10 Cobra tubes Fly has been talking about for ages.
Tricks of the Trade: Episode 1