Swingbuster,
Forget the toes, what about the center? Pujols can "drag his toes" and keep his center in place.
Or, better yet, measure the head movement. Clark's head moves forward several inches from the time he puts his front foot down until he makes contact. Most MLB hitters hold their head virtually in place during this phase. Epstein's "pole through the head" analogy is a fitting description.
http://www.youthbaseballcoaching.com/mpg/Chipper01.mpeg
This Chipper Jones clips is a good representation of this.
The forward momentum during the swing demonstrated by Clark is increasingly rare in MLB (OK, Ichiro).