Actually, tubs in 24" are relatively easy to find (In comparison to clincher tires). Tufo makes one, and panaracer makes one. Andrew Muzi at yellowjersey.org has a few of them. The problem is rims.

Apparently, panaracer makes a 24" clincher tire, and I have a velocity aerohead on order, but I'm getting sick of waiting. I FORGOT to bid on an ebay auction for a 24" front wheel for flipping $21USD.

Needless to say, I'm quite angry at myself.