Nice! I really like this little movie showing off the genetic learning that went into teach a bi-ped to walk:

http://www.naturalmotion.com/files/simplewalkevolution.mpg

Endorphin does look promising. I've just read a little review of it in Game Developer as well. Will definitely look into it.

I assume you've all seen Ken Perlin's somewhat simple but powerful procedural biped demo, that he's been demoing over the past few years?
http://mrl.nyu.edu/~perlin/experiments/emotive-actors/

(he may have a spiffier version that's not yet online)