The alternate interpretation that this person will be designing whole systems is equally plausible to me, especially given their investment into the Linux space. Initially, that move didn't make a whole lot of sense because the Linux desktop space is so small and (particularly where issues around graphics drivers and the like are concerned) requires a fair bit of technical acumen. A ChromeOS-like strategy makes much more sense, though: heavily tailor the OS user experience to fit your specific target audience, and vertically integrate so you control the hardware, and the user never has to touch drivers or configs. Then it's not "Linux," anymore, it's "SteamOS" or whatever.
Actually it seems as much to do with the more solid "Valve has a patent on a controller with swappable parts". Said patent is here: http://www.faqs.org/patents/app/20110105231
But yes, there is a lot of speculation, of course.
His blog is really interesting and definitely worth following.
G+ profile: https://plus.google.com/115054970849159689228/about
A post on his blog where he discusses his previous business and mentions working at Valve: http://benkrasnow.blogspot.com/2012/08/tour-of-bens-shop-201...