Here is are some other stores that sell x0xb0x kits or 303 clone related things.
x0xsh0p.de Has kits, parts and a cool VCO mod.
rv0.be Get your x0xlarge CPU upgrade here. Also has panels and a few other parts.
abstraktinstruments.com If you need a non DIY analog 303 solution the the avalon bassline is the way to go.
shop.re-303.com DinSync is working on getting a exact replica of a TB-303. The ultimate 303 clone