I work for an indie game studio in Boston called Proletariat. We just released a free download of the character rig we use on all the characters in our game, World Zombination. Our animator Sterling also wrote up a blog post on how we got there.
We're really excited to share this, so please check it out and let me know if you have any questions!
http://blog.proletariat.com/post/72769937365/world-zombination-character-rig-postmortem