Not possible (yet) in CS6.
Considering that Adobe considers the dark interface now as one of it's "notable new features in CS6", among inline naming of layers and "more than 40 new enhancements to the UI"... I wouldn't suggest to them at this point that there are some people that prefer just plain old white.
I mean, white truly is intimidating metaphorically speaking for designers due to the proverbial "blank piece of paper" staring them in the face. That is to say, that Adobe is truly looking out for you psychologically speaking to have a Happy Illustrator Day™ with gray-on-gray as the lightest available tone combo, and you just plain don't want "to see it"... literally speaking....
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