Website Giz-China has published photos of what appear to be genuine white iPhone 4s on sale in China. The boxes are marked with a label describing them as being "for internal use only," and certainly look more convincing than many of the knock-offs we see from that area.
Prices reportedly range from 5500 Yuan (about $828 as of this writing) to 8000 Yuan ($1204).
This type of illegal resale has been a persistent problem for Apple. In 2008, the New York Times estimated that there were 1.4 million ill-gotten iPhones in the world. At this time last year, the Wall Street Journal estimated that number had grown to 2 million in China alone.
More recently, security personnel at a Beijing Apple Store were forced to temporarily close the doors while some customers purchased huge numbers of iPhones only to re-sell them just outside the store. Additionally, Apple has begun to introduce new products to the Chinese market more quickly than before, partially in an attempt to eliminate the high-demand, low-supply environment that's so attractive to opportunistic resellers.