The developer of the public transportation guide for San Francisco, iBART. Has spotted an iPhone3,1 user in their log files. This is similar to when the 3GS was spotted before it was announced by the device string in log files.
“iPhone3,1” was first spotted in Pandav’s usage logs in November. The identifier “iPhone3,1” does not match any shipping iPhones. The last iPhone released was the iPhone 3GS which carries the identification string “iPhone2,1”.
If the reports are correct the next iPhone should be around in about 8 months, if the cycle is the same as before.