Hardware Idea

For all you talented hardware guru's out there :

I've often wanted a adaptor that would allow me to hook up any kind of small single board computer that has an IO pin breakout to the atari. Some way to map the pins into the memory space, and read and write to them. Boards like the Arduino's and the raspberry pi's, for instance. Seems like you could do an awful lot with an interface like that. SIO and so forth really is just too slow for anything other than emulated disk Drives.

Just a suggestion.