Ars points to a USBDeviceConfiguration file which lives in the iPhone SDK 3.1 which has a surprising new addition that could signal an upcoming tablet. Included in all of the recent iPhone SDK updates until now has been the iProd 0,1 device file. 0,1 device files typically stand for prototypes.
As of iPhone SDK 3.1, there is now a new device profile . This device file has been updated to 1,1. Theoretically, this means that production devices are already being trialled on iPhone OS 3.1
