The Isshu only rule is silly if it applies to qualifier tournaments outside of Japan - Japan may have had Black and White for a while now, but the rest of the world will have only JUST gotten the games by the time the tournament comes around...
I walked into a GameStop the other day and looked through the game book. It said that BW would be released n April (can't remember whether it's at the beginning or the end)...and last year (or should I say the 2010) qualifier rounds occurred in May and June. I guess you better plan your team right now and be ready to build it as soon as it comes out...