Somewhere on this site there was a discussion about some woman over in Britain who, in fact, already has a white iPhone4. I will probably never find that article again but I know I saw it. Something like Apple gave her a choice of white or black and she chose white.
She probably does not realize that she has the only white iPhone in existence and how rare it is. If she were to put it on ebay, I bet it would fetch 20-30 grand easily.
It wasn't her iPhone. It was a review unit sent by Apple (she is a Tech Editor for the Telegraph).
http://blogs.telegraph.co.uk/technology/shanerichmond/100005297/white-iphone-4-mystery-solved/