SEGA making a Steam Machine would be amazing. Imagine, SEGA Europe and SEGA Japan working together (I know, when pigs fly) to develop and design a Steam Machine that is best suited for SEGA's PC output. Bring in past SEGA hardware all-stars like Hideki Sato and Masami Ishikawa (they're still active, right?) as consultants and design a case that evokes past SEGA hardware. I don't mean a Saturn with PC components inside, but a machine that looks like the logical evolution of SEGA hardware. Pre-load it with a mix of games, like Sonic Generations, the latest Total War, Football Manager, and Valkyrie Chronicles. Include a special edition Steam controller.
I'm certain SEGA fans would plunk down a fair amount of cash for one of these, and it expands SEGA's PC audience.