OK. I just watched highlights of a minor-league game between the Staten Island Yanks and Brooklyn Cyclones game. The Yanks have a pitcher, Pat Venditte, who is ambidextrous. He has a 6-finger glove with two webs in it.
Anyways, he gets the first two guys out right-handed and then a switch-hitter comes up to the plate. Every time Venditte switched hands, the batter crossed the plate to hit the other way. After a couple of minutes of this nonsense, they forced the hitter to pick one side (he chose right) and to stick with it.
Venditte struck him out. Entertaining stuff.
I have looked around and here is some video: The Official Site of Major League Baseball: Multimedia: Video Playback Page