I went to the Apple Store Sydney tonight to check out their iPhones. Out of the 12 white iPhone's on display, 5 of them had some sort of cracking to various degrees. I could not see any cracking on the blacks, probably because it's too hard to see them on the black iPhone if they're there.
I spoke to the head iPhone sales guy there and he wasn't aware of the issue. I told him I wanted to buy a white iPhone but if it had cracks I would want it exchanged, and he said they wouldn't take it back for slight cosmetic damage only.
I want a white iPhone but I certainly don't want any cracks, I'm not sure if there are other return options possibly through the carrier (optus) if it were to have cracks. Right now I think I might just have to get the black one instead.