The Steam Machine is slightly bigger than a portable Blu-ray / DVD player. (I just checked this with my own players)
I can’t wait for someone to make the equivalent of the Gamecube’s GBA Player for discs. Because of its size, It could even be a plastic shell where you put an existing Hitachi/LG portable drive without having to disassemble anything
Reminded me of the Panasonic GameCube (Panasonic Q). Not a separate DVD player, but built-in. Still, interesting ideas and neat designs!