Something of a tangent:
There are these 3 clips of Tohei sensei on Youtube at the moment, and in one of them he shows striking a bokken corectly and incorrectly. (7:30 in http://www.youtube.com/watch?v=qfpTU6ZiaK4
There is also an Aikikai video (not on Youtube) featuring Kisshomaru doshu, with Shibata, Seki, Moriteru, Endo, Suganuma, and Chiba senseis as ukes. In one part Chiba sensei is thrusting at Kisshomaru with jo, and Kisshomaru doshu strikes the jo with bokken in such a way that Chiba sensei drops to his knees.
I just thought is was interesting you could see them do something so similar in light of this thread.