A minimalist commercial just aired on Monday Night Football and it did not tell a whole lot of information. Most of the time is spent as a rectangle text input (reminiscent of a Google search) changes shape until it reaches the dimensions of a smartphone. It then adds Oct. 4 and the Google logo next to the shape.
The YouTube version of the posting adds a little more information:
Something new to love on Oct. 4. Get in the know at google.com/tenfour
The website redirects to madeby.google.com and does the same rectangular shape followed with a slideshow of pictures that could serve as cases.
From the rumors, we anticipate Google to announce the next Nexus phones at that event, codenamed Sailfish and Marlin, but they will go by a new name: Pixel (and Pixel XL).