I had the oppertunity to sit in on a meeting of IFMAR officials at the Off Road Worlds back in October where this issue was brought up. Bob Novak has presented IFMAR and its member Blocs with proposed rules regarding a seperate brushless class. This is in it's very beginnings right now. If Brushless motors are to be allowed at a National or World caliber event, it sounded like they will try to keep them seperate. I do have to commend Novak for coming up with a number of guidelines that other manufacturers either already meet or could easily meet.
As far as brushless in other classes....IN the Limited mode, guys running stock here are faster then the brushless class. In unlimited, they are only a few tenths faster. The challenge with the brushless motors as they are currently is that all the power and torque (or at least a lot of it) is on the bottom end. If one of the manufacturers could come up with a "Real" speed controller,one with different throttle curve profiles or even (god forbid) one with a current limiter to soften up the bottom end and make it more driveable. A lot of people have used the throttle expo on their radios to help, but this only does so much.