According to a recent CyclingNews article, Mark Cavendish downsized from a 52 cm to a 49 cm Specialized Venge this year.
The article quotes Specialized Body Geometry fit manager Sean Madsen:
"One thing about Cav is that he likes to periodically change his position around, based entirely on his feeling," Madsen said. "He may change it back in a couple of weeks, when his mood changes!"
So did he change his position? Here's some BikeRadar/CyclingNews reviews of Cavendish bikes:
I took the 2011 and 2014 side shots. Unfortunately these are from relatively different camera positions. To compensate, I did a combination of image scalings, rotations, and perspective transformations on the images to match the bottom bracket positions and the heights of the front and rear tires. This is 3 transformations for 3 constraints. It's not enough to fully match the photos, but it's a lot better than taking them unprocessed. I aligned the front chainrings, since this should align the bottom brackets, the standard of reference for bike position. I then did a superposition GIF animation.
I don't see much of a position change. The 2014 bike has spacers to correct for the difference in head tube length. The front-center of the two frames appears to be fairly similar.
Okay, don't be lazy: I can check to see if this is true. Here's a geometry chart:
Indeed the front-center is identical. The smaller frame has more trail. Maybe Cavendish likes the feel of more steering stability.