http://www.animationbuffet.blogspot.com/ And in particular http://www.animationbuffet.blogspot.kr/2010/05/tresher.html That's your best bet for a complicated creature rig that's similar-ish to what you're looking for.
Work in progress on a creature based on some concept art from Dead Space. Not happy with a few parts but probably need to mess around with it a bit longer.