I apologize for the necro post, but I'm bumping this thread for two reason:
1) JodyH and Slavex's posts in this thread are excellent.
2) I am looking for suggestions of other drills, other than command fire (that Slavex posted about) that can help me improve speed of movement off my timers beep. I did some slow motion video and my hand is barely getting to my gun before the beep is over on my concealed draw stroke, and I think that's pretty slow. Basically I want to decrease my reaction time to the beep. Any suggestions?