As someone who deals in export/import from China here is my take-
The factory that make the iphones will be under and agreement to make the iphones. They are strictly regulated, materials etc are all recorded. Any materials that are missing they will check on it. This is to see if the factory are making unauthorised batches without Apple's knowledge.
Secondly the factory will have a contract, if this is broken the factory will have to pay a fine or some sort of compensation. This is a very large amount. It also means they lose this contract to produce the phones. In any economy they will not want to lose this at all. These contracts are worth 10's of millions ($), even more to the factory owners.
The factory WILL NOT risk this contract by making batches without apples consent just to get a few $10k+. This is the same situation on any electrical goods in demand, PS3, XBOX360, Kindle etc etc. Anyone who says they can supply these, they are talking BS. The only people who can do this are distributors, and they will not go on forums like these to sell them. I hope this serves as a warning to anyone on this forum intending to buy goods.