AE CS3 has a bone/puppet system.
Its not bad, definately not perfect, but all in all I think it’ll give you what you’re looking for.
Download the demo, see if you dig it, and you’ll have 30 days to figure out if it is worth the investing. Personally, i really could have used it a few months back.
I’ve had a lot of luck with ccbend/ccbendit with applications like that.
Nicholas Toth
Freelance Animator
nicholastoth.com