It's beginning to seem entirely possible that PC gaming powerhouse Valve is working on its own "console" (or at least custom PC). Especially when you consider that it's been working on control pad designs for nearly three years.
This patent, first filed in 2009 and published in 2011, is for a "Video Game Controller" featuring "user swappable control components". In other words, a control pad where you can mess around with the style and placement of some of its inputs. Something explicitly mentioned in the original report on the Valve machine's existence.
While that report mentions things like biometric feedback, similar to the technology found in Nintendo's missing-in-action Vitality Sensor, this patent sticks mostly to the concept of swappable components, illustrating examples like switching the placement of thumbsticks, and replacing them with extra peripherals like trackballs.
Conveniently, it seems the controller is "smart", in that it can detect the type of modular component being installed and configure itself accordingly.
It was submitted by three Valve employees - Mike Ambinder, Steven Bond and Scott Dalton - and Valve Corporation is listed as the assignee of the application, so we know it's an official, in-house project.
What we don't know, and this is important to remember, is whether this thing still survives in this form. If this Valve "console" is indeed real, the capabilities of its controller may well have changed in the months since this was first submitted.
It's also important to note that this is a patent application, meaning the appearance of the controller is only for illustrative purposes (perhaps based on a prototype unit, using an Xbox 360 pad as a base), and is not necessarily indicative of any actual designs Valve is working on.