Dreamcube017 (5/3/2013)
I've not tested the collision yet but I know for a fact that iClone supports custom spring chains already.
Not only that, but it also has toon rendering. You can get it to look like the MMD renderer if you mess with the toon settings a bit.
Soooo actually all that stuff's already there. You'll need 3DX Pro though.
Oh and also you can get a bunch of MMD style characters off the net and from games that let you export the characters.
This should point you in the right direction.
https://sites.google.com/site/mikumikubeat/3d-custom-girl
I like the way the "3D HAIR VOLUME" is defined with minimum lines in MMD and the shader for hair and dresses is quite interesting.