I've been working on a mouth open morph. Actually, I'll probably be doing that for a while, making several different shapes. For now I've uploaded a zip file to the Head Shaping Morphs section of the dev site named "MouthOpen03.zip" It contains 2 MT's - one for the head and one that corresponds, for the lower jaw.

It pretty much just opens the mouth and doesn't do anything fancy with surrounding muscles. It's part of an entire face rig I built to make it easier for me to make more, and more varied mouth and phoneme morphs, but I'm uploading it in case anyone wants to mess around with it, use it for further morphing, anything like that.

The advantage to this is it doesn't include the head-bobbing effect. ;-)