I've been toying with doing this for a while. Haven't been entirely happy with the results of my various tests yet, but once I am, I'll start a new thread for it and post a link to it in this one.
I don't have even a rough timetable, mind you - again, I'm just toying with tests for various scenes right now. I might eventually decide this can't be done to my satisfaction, but I hope that doesn't end up being the case.