"For years, Valve has been all about writing software that provides great gameplay experiences. Now we're developing hardware to enhance those experiences, and you can be a key part of making that happen. Join our highly motivated team that's doing hardware design, prototyping, testing, and production across a wide range of platforms. We're not talking about me-too mice and gamepads here - help us invent whole new gaming experiences."
The quote above is the introduction to a job posting on Valvesoftware.com, and adds gasoline to the Steam box fire. The listing looks for an Electronics Engineer and the job description is as follows:
"Work with the hardware team to conceive, design, evaluate, and produce new types of input, output, and platform hardware"
It may sound as if Valve is still in a prototyping phase, but who knows how far the work has come.