Right now iPhone 5, like any dark matter, can only be observed by its effects on others, including the log traces it leaves and the cases manufacturers leak. This time it's TechCrunch, citing an undisclosed developer who's iOS app, points to records of a never-before-seen dual-mode GSM/CDMA world phone.
The logs show that the app has been briefly tested by a handful of people using what is almost certainly an iPhone 5, evidently running iOS 5, sporting two distinct sets of mobile network codes (MNC) / mobile country codes (MCC). Those codes can be used to uniquely identify mobile carriers.
Sure enough, some registrations for the app – which the developer also asked not to be named – were logged from a new Apple device, using the MNC/MCC codes from both Verizon and AT&T.
Apple has had theoretical support for a world phone since switching to Qualcomm chips, but previous iPhone 4 models haven't enabled the feature. Turning it on would likely be bad news for those hoping iPhone 5 would sport LTE (the faster and closest to a "real" next generation wireless technology). HSPA+, a not-quite-as-fast but far more widespread "4G" protocol looks like a safer bet, though it would leave Verizon behind on the same EVDO Rev A speed the current iPhone supports. (See TiPb's guide to wireless network terminology for more on what this all means.)
In other words, Verizon could advertise a world phone but AT&T could say they have a 4G iPhone.