This is gonna hurt
Dennis Hatch for one. Go check out some of the Mosconi cup 2010 stuff up on youtube. Dennis drops his tip in behind the ball where he wants to hit it.
Please name the pros who do this.
I can't think of any, except Charlie Williams, and the only time he does this is after he gets down and the shot doesn't look right. Then he gets up off the shot, walks over and examines the spot on the object ball, and goes back down for a 'new look'. I know this because I took a lesson from him.