We all know the next iPhone is going to sport some new silicon, almost certainly a variant of the A5 found in the iPad 2. And it appears that some very special developers have been given iPhone 4 units with A5s inside, presumably in order to have some A5-powered games at launch. This from an anonymous report to 9 to 5 Mac, in which the units are also described as essentially stock iPhone 4s otherwise.
Interestingly, despite having the new hardware, the units are reportedly still running a version of iOS 4. I would have expected launch features to incorporate iOS 5 features, but hey.