UPDATE: We acquired an image of the non-final controller being handed out to Steam Dev Days attendees. It's identical to the controller Valve demoed at CES. The area in the middle where the touchscreen would be is a grid of four buttons.
As you can see from the mock-up controller, the design is still going through a pretty radical change.
The original story appears below:
Valve's Steam controller is getting a slight redesign and it isn't even out yet. According to posts from Steam Database, the Steam controller is eschewing a central touchpad in favor of two sets of physical buttons. You can see the new mock-up and the original design in the controllers above.
The controller will use two AA batteries, and the blog says that Valve is "keeping VR in mind while developing the controller."
Valve is currently hosting the developer-only event Steam Dev Days in Seattle. Attendees were given their own prototype controller in a goodie bag, and they will also receive a Gigabyte Steam Machine.