OK, talked to my buddy John over at Blizzard. There is a bug, but the fix depends on a number of different things including what video cards you have in Sli, if there is a 64 bit AMD chip, is there 2 gigs of ram or not, etc.
Basically, the easiest fix is to use some program he called "nHancer" that allows you to create profiles for your system and if you are using a geforce 7900 then just disable sli for Wow. He claims that there isn't much of a performance boost as the textures are too simple to require that much power. He says you might have gone from 60fps to about 68fps. This completely ditches the Alt/Tab issue. (btw this issue has to do with tabbing out to the desktop, and then when you come back in the VSync on Wow crashes and either the system freezes, Wow freezes, or the top half of the screen works but the bottom is either the windows desktop or a flickering between Wow and the desktop.)
Now, if you want to try some fixes for the heck of it apparently you can use SFR instead of AFR at login. You can disable "Triple Buffering" and "Vsync" in the wow config. These things may fix it, they may not. Different results for different people based on the system config differences listed above. One issue you may or may not see is items that stutter when you get near them if you have sli enabled and vsync turned off. Not all machines are doing it, but apparently some do.
One thing he mentioned was that the expansion should have much better Sli support. But he did keep returning to one fact: Mike...you don't need it. We just don't push the texture complexity of Half Life 2, Fear, Oblivion, Dark Massiah, Doom 3, Crysis, etc. Our stuff runs on 3 year old machines. One 7900 should run wow at 1920x1200 at over 50fps all the time.
So I hope this gives you some suggestions. I have no experience with this app called "nHancer" so maybe some folks in here can vouch for it. Should I be using this when my m9700 gets here Tuesday?
If you guys have any other questions on this issue, post them and Ill get em over to Blizzard.