This sounds cool. I've been waiting for this kind of technology for ages.
Years ago, a project was in the works called Gemeni Man, about a futuristic bounty hunter or something, who is the target of assassination by his younger clone. It was going to star Harrison Ford and use CG technology to de-age him for the younger version. I guess the technology just wasn't there yet, but when it's perfected it's going to be a very useful tool indeed for film-makers, especially when dealing with iconic actors whose younger appearances we are very familiar with.
To do this for a whole movie would be a great test of the technology, and I can't wait to see the mentioned scenes in X3.