Going back to my exclusive Linux time with Gabe and their early Linux team and the special Linux delivery to Valve Software, I've known that a pure Linux-based gaming console built around Steam was in the works.
Since that point last May there's been hints of Valve's console ambitions with Steam Big Picture and other initiatives and minor chatter from Valve employees. In December was when Gabe Newell publicly commented on their Linux-based game console plans. As I have said already, it should ship in 2013 and will be running a pure Linux (non-Android) stack and should be a more "open" gaming platform than the PlayStation or X-Box while being more friendly towards game developers/studios looking to distribute their titles over the wire with Steam.
Golem.de. For those non-German speakers, here's the Google translation. Basically this latest independent article just states that Valve's working on a Linux game console and should be released in the 2013 calendar year. These recent comments are from Valve's Ben Krasnow, a hardware engineer at the company.
If you missed it, 2013 Is Going To Be The Year Of Linux Gaming as the problems with gaming on Linux get addressed.