I just exchanged my black lumia today and asked the sales rep if he was also selling the white one and he said yes. Brought the black and white ones both out and I tested both for camera button, screen clicking. The new black one had no screen clicking in the top left corner and and the camera button didn't need excessive travel. The white had a slight clicking in the screen but not as bad as my original black one. Since the white one he brought out had the clicking I decided to go with black again instead of getting him to go open another white lumia. So far my new black one has been perfect. The nasty sound from the vibrator is not present, the camera button travel is great, the screen doesn't click, the power button is more stiff. I feel like the reception is better (same location, one bar higher than the old one) and the screen is more responsive, but that's probably me.
I asked the guy how many white lumias he had in stock and he wasn't allowed to give me a definitive number but he said at least a hand full.