After doing a bit of playing around, focusing the camera manually while recording a video is really easy. It shouldn't be too hard to bind the appropriate commands to the volume keys, giving you manual focus while recording. Autofocus on the other hand would need something a bit more intelligent, but the hardware is definitely capable. Maybe gst-opencv could be of some help. If not for autofocus, then at least for cool things like face detection and face blurring.

See http://www.youtube.com/watch?v=k5TqbtXwLpQ for a horrible quality video of it.