Xi3 interview with Destructoid both clarifies and obfuscates 'Steam Box' possibilities.
The 'Steam Box' has long been rumored, and it has appeared as though this year's CES would be its official public introduction. Not so according to a post on Destructoid, "Yes, Valve is in cahoots with Xi3 Corporation, and there's something neat on the horizon, just as we heard earlier today. But the new tiny box form factor computers debuted at CES this week are not necessarily the long rumored Steam Box. That's something that's just a bit farther down the road, unfortunately."
The article went on to focus around specs for the Piston before relaying one reason for the confusion, "Xi3 is not using the name 'Steam Box' while discussing this project. They don't mind throwing around "Piston" at all, though. When I called their upcoming device a 'Steam Box' during our chat, one Xi3 rep said, 'You called it that. Not me.'"