TUAW sources inspecting the USB device files in yet-unreleased iOS 5 firmware have discovered suggestions of two future iPad 3 models as well as a pair of iPhone 5 models. What's most surprising is a big omission: no mention of an iPod touch 5.
Specifically, there are declarations buried in the iOS system files that reference "iPad3,1" and "iPad3,2." Likewise, "iPhone4,1" and "iPhone4,2." The iPhone 5 will be a 4th generation unit because the iPhone 3G was technically 1st generation. This throws off the numbering and confuses everyone, so don't fret if you were confused.
[As MacRumors notes, the iPhone future models were already visible in beta versions of iOS 4.3 earlier this year. –Ed.]
Interestingly, there are no mentions of a new iPod touch. If there really is no iPod touch 5 ready to launch in September (the typical iPod refresh time), sources believe it could be because Apple is reserving the spotlight for another member of its iOS family, namely the iPhone 5.
Of course, experience has shown that model registrations do not mean that these items always become an actual shipping product. For example, it took almost a year for the iPhone 3,3 (the iPhone 4 for Verizon) to ship, and the iPhone 3,2 never became a product. Sources believe that's because alleged carrier deals probably fell through for a third iPhone 4.
[We had those phone models backwards! The iPhone 3,3 is the CDMA iPhone. See, it is confusing. Fixed. –Ed.]
We'll know for sure in the upcoming months, but until then, these tantalizing hints will have to do.