They already do that with many of thier TV shows on espn.
I was floored weh I used to watch Mike and MIKE before work, they had a SD studio and finally went to an HD new set and they looked great, then the next day, they showed up and they cut off the EXTRA with a "Whats coming up" wall.
WASTED space for HD.
Basically they went to an HD format with an HD Feed on a 4x3 screen with the side taken out like that ... always thought that was a stupid thing to do.