The folks at iFixit have taken one of Valve's 300 prototype Steam Machines apart and the results, while about what you'd expect, are still pretty cool nonetheless. It's remarkable just how much they're able to fit in such a small box.
The site also did a teardown of the still rather strange-looking Steam Controller. I can only imagine what a pain it'd be to have to put that thing back together.
Steam Machine Teardown [iFixit]