That's insane

http://www.worldofraids.com/wow-blue-tracker/us-forums/27401643624-blizz-the-insane-and-cataclysm.html

Insane in the Membrane is a feat of strength, not an achievement. Feats are things that you can't be guaranteed to complete, which is why they're feats and not achievements. ... It's possible that in some very specific situations where someone has completed the reputations which are being removed, but not others that will still be in the game, that it can still be completed. But it's something we're waiting for clarity on, and will let you know as soon as we do.

If you are running for Insane - have a look at what reputations will be removed when cata drops, and concentrate on them first.

If you supply to the 'Insane' crowd, point them at the above thread, and encourage them to quietly panic, and buy lots of stuff.