Yes, it's possible... yes, I did it. Here's the screenshot to prove it:
Booyeah
Okay, so the framerate is really quite poor and the sound clicks a lot. I've heard there are some Wine DLL tweaks that you can do to the VM that can fix these, although I don't know how well.
All in all, I'm quite surprised. The performance isn't exactly good enough to make it fully playable, but it's great to be able to check my WoW mail once in a while from Linux...