> Is there even a desktop/window manager work with 3d space currently?

The best known is perhaps https://en.wikipedia.org/wiki/Project_Looking_Glass but there's many others, at varying stages of development. It will be interesting to see if custom OS/UX development is made available for this device. We'd also need quite a bit of custom development to make the OS comprehensively usable with gamepad-like controllers alone (no mouse or keyboard required). The existing work on "10-ft." media center interfaces can provide a useful starting point for this but it's far from covering all possible uses.