I've written a set of scripts, including a custom AC action, for working with facial expressions based on texture animation, as seen in this quick demo:
https://youtu.be/HiIaBbe2pA0
If anyone else is interested, I'll polish it a bit for general use and put it on the wiki.
Comments
I know this post is pretty old but did you ever publish the scripts? It's something that would work pretty great for the project I'm working on now.