http://www.appleinsider.com/article..._gen_ipod_touch_ipad_and_unknown_product.html
no more black plastic, woot
According to people familiar with the matter, the latest beta of iOS 4.1, due to ship in the coming weeks, includes three new "Configuration Descriptors" within its USB configuration files -- all of which pertain to devices that list "Apple, Inc." as their "manufacturer" -- as can be seen in the screenshot below.
The first product, a fourth-generation iPod touch, is referenced within the code as "iPod 4,1." That particular identifier indicates the device will be the first iteration of a fourth-generation device, rather than a revision to the touch's existing design, which would have been denoted as an "iPod 3,2."

no more black plastic, woot