Apple's annual developer conference in San Francisco.
October 2009 iPhone 4 Prototype Shows Up on eBay [Update: Listing Pulled]
A number of high-quality photos are included with the listing, showing a complete lack of Apple branding on the exterior of the device. Most notably, the Apple logo has been replaced with a distinct logo that was previously seen in a Twitpic posting in February 2010. The standard "iPhone" text on the rear of the device has also been replaced by "Prototype", along with text noting that the device has not been approved by the Federal Communications Commission and can not be sold until such authorization is granted.
Sonny Dickson has also provided an overview video of the device showing off several of the features of the device including the software and a lack of screws on the bottom of the device that is consistent with some of the earlier leaked prototypes.
As seen in the video, the serial number of the device indicates that it was manufactured during the 43rd week of 2009, which corresponds to late October, nearly eight months before the device was made available to the public.
The auction for the prototype currently carries a single bid of $4,500, with the seller advertising in the listing that a $10,000 offer would be acceptable to halt the auction process and simply purchase the device.
Update: The listing has been removed.