William Shatner is doing this now in his new venture 'Live Autographs' (as an investor and partner). It's a new video service in which celebrities appear on camera to deliver a personalized greeting as they sign an autograph. He gives the customer what they want (most of the time -sort of) for $149.

Excerpted from the article -

William Shatner sat in a drab office staring at a TV monitor displaying a message he was supposed to read to a fan while signing an autograph, but "Star Trek's" Captain Kirk wasn't very happy.
"I can't do this, this is crazy," Shatner said.
"Are you nuts? You want me to say, 'When I'm smoking and sipping whiskey with Allen' — who's Allen? — 'I'm secretly thinking of you and your dog?'
"I can't say that," Shatner added, glaring into the camera, his words dripping the trademark irony he has summoned in countless TV performances, including his Emmy-winning role as Denny Crane on the ABC courtroom drama "Boston Legal."

The complete news article can be found at http://www.washingtonpost.com/wp-dyn/content/article/2008/08/14/AR2008081403016.html .
It's high tech autographing for a princely sum.