This was a problem for me a while back, but over the years, I managed to get a somewhat realistic walk. It contained the head bobbin, feet turning, and correct movement of a normal walk. I can't remember what project it was exactly, but I remember making a game using the system. It was before it was finished though so it's not the best, but here it is.
http://www.alice.org/community/showt...6144#post26144