DCI had addressed this years ago. Back when their used to be a DCI all stars (macy parade) the idea was batted around. Lots of logistics involved, including rehearsal time, getting people from all over the country to central places to practice, shows that would involve 360 degree viewing (as opposed to playing to the "home"side") housing, feeding (for 500-800 performers) etc.. If you're going to debut DCI on the world you want to "get it right" and put the activity in the greatest professional light possible. So far that hasn't happened. Same talks about the Olympics (all star groups)
Who's going to play the Super Bowl 2012 Halftime Show?
I believe it should be Aerosmith. If they are looking at someone that is currently in the the middle of pop culture that would appeal to a wide range of audience, Areosmith is a good option. Steven Tyler being quirky on American Idol sure helps his fan base, both young and old.