Damn, I'd seen those before but could never seem to track down; badum-tish, anyone that sold them... mainly as I couldn't seem to work out what they were called. Rubberised Timing belts and Seamless Rubber Timing belts got me close but I was never able to buy any.
Stating the obvious, but with the Speed 900's gone I wouldn't start building a new robot around them :P Aside from that, they should be brilliant!