As Valve has promised, they have been working diligently to get 3rd party manufactures to start offering Steam Boxes. Today, we get to see the initial list of hardware manufactures which include: Alienware, Alternate, CyberPower PC, Falcon Northwest, Gigabyte, iBuyPower, Material.net, Next, Scan Computers, Webhallen, and Zotac.
This list is still in development so more companies can be added at any time. Considering that CES is currently underway, there is a good chance that more manufactures are coming soon.