Staff edit/update - word on the street is Valve may indeed be "licensing" the design and this might just be one of the potential models. More on that development http://gbatemp.net/threads/valve-piston-is-only-one-of-multiple-hardware-prototypes.340769/
So, we got some new informations about Valve gaming system. It will be manufactured by Xi3, and should offer 1TB of memory and a 3.2GHz ADM CPU. No information about the GPU. It looks like RAM and CPU will be upgradeable. Piston's performances will be based on Xi3's "X73 model".
More info : Source (Polygon), Xi3 website
My thoughts : Kind of useless for people who are already into PC gaming, but it's still a good opportunity for the others (depending of the price)