iPhone 5 unlikely to have NFC
iPhone 5 Render Based on Leaked Parts

Brian Klug and Anand Lal Shimpi of AnandTech have said recent part leaks, especially the metal back plate, are an obvious sign against NFC in the next generation iPhone.

"Given the primarily metal backside of the new iPhone, it’s highly unlikely that NFC is in the cards for this generation. In fact, given the very little space at top and bottom dedicated to those glass RF windows, you can almost entirely rule it out."

Given Apple's history I would expect that they don't feel NFC is worth betting on and have something else up their sleeve.

Be sure to hit the source link for a more technical explanation.

Source: AnandTech