I'm designing Haphaestus for interaction via classic TV remotes, but once I get that working I think adding support for classic game controllers.
Basically: Add a joystick! Remove numpad.
This would allow me to scroll, & there's an "8pen" idea by which typing would be a lot easier!
Also I know someone who'd be interested in eventually building a ereader based on it... That would lead me to tackle hittesting (depending on hardware) & text-selection...