that sounds cool... please keep this thing in mind that there should be some easy way to scale the biped according to the model...i m just mentioning it cause one of my friend has this script...which works like Character studio for max(same biped thing)...but its not very easy in that to scale the biped geomatery(skeleton) according to your model.... since then we had been looking for somethin like you have mentioned....
wish u best of luck with it and looking forward to see it ....