Thanks to Mike here is a picture of an advertisement for an October 20th release date and exclusive Steelcase packaging for Transformers: Revenge of the Fallen. I believe the exclusive is through Trans World Entertainment Corp stores (FYE, Sam Goody, etc). The chain also had released the Steelcase packaging for the first movie that was comprised of the Autobot and Decepticon logos.
Nothing official has been announced by Paramount but this is the first release date on DVD & Blu-ray that can be considered credible. October 20th is the first leaked date that actually matches the traditional Tuesday release for new movies in the States and also the first time a date was seen outside of a website placeholder date. The first movie was also released in October and was considered the top selling movie of the year. On a more practical level retail chains generally avoid releasing incorrect information to customers as signs cost money and bad information provided customers can too. Hopefully Paramount will issue something soon to verify a definitive date for the release of the movie on home video.