iPhone 4 prototypes with 64GB capacity available in China

On the "grey market" in China, certain iPhone 4 prototypes have started to be put up for sale, which to everyone's surprise have an internal capacity of 64GB. Those who sell them I support that these prototypes were "taken" directly from the Apple factories, they come with iOS 4.1 pre-installed and as you can see they have special series for prototypes. These devices have appeared in Hong Kong, but no one has yet been able to confirm whether the devices are really real and the sellers claim that they have very few prototypes of this type available for sale. It would not be abnormal for Apple to test a 4GB iPhone 64, but it would be abnormal for these prototypes to appear for sale in considerable quantities.

According to Unwire.hk, this suspicious 64GB model has started selling in Sin Tak, the largest gray market in Hong Kong, and the sellers claimed that these are engineered models and available in small quantities.

What is your opinion, is it possible that certain workers of Apple's partners have stolen some prototypes from the factories?