Sorry to raise this thread from the dead, but gathering knowledge of all of the Elimination Tournament clans, where the majority of the professional community lies, would be pretty easy. Some time and dedication on each server could lead you to one clan, and they'll almost certainly have rivals which they'll tell you about.
The only real problem is servers. Time delay, even if evenly experienced by both teams, is sure to cause... dissent. There is certainly not enough people on Azeroth for such a tournament... unless you want maybe forty people.
Problem being, or not being- I haven't seen a professional clan for Elimination Tournament II pop up yet, most of them like to stick to Elimination Tournament I. Some clans are a bit of a mix.