Prominent iOS developer @Chronic seems to indicate in a series of tweets this morning that there is indeed NFC hardware in the iPhone 5 (or at least prototypes), but it perhaps is not set up to be used for payment systems.
Just as a note: The iPhone had the capability to use FM RX/TX radio for years, but Apple decided not to enable it for listening to radio stations or even broadcasting to your car stereo for whatever reason. This could be a similar situation.
We will not know for sure until the iPhone is torn down later this month.
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