It would seem largely pointless for them to build their own distro from scratch. On the other hand it should be relatively trivial to make a spin of say an Ubu

It would seem largely pointless for them to build their own distro from scratch. On the other hand it should be relatively trivial to make a spin of say an Ubuntu LTS that boots directly into Steam "big picture mode" directly on top of standard X11 without a Window Manager. In theory I suppose they could ship this with a standard set of hardware that was subsidised and end up with something that looked more like an Xbox.