It would be real nice to have a peripheral API that could output all sorts of fun things. Raildriver input is one thing but it would be nice to be able to grab telemetry and say, write it to an Arduino serial buffer to drive homemade peripherals. Speed, speed limits, brake pressures, destination/timetable information, safety system outputs/configuration, and so on. A neat idea would be a homemade PZB controller -- the three control switches and the ability to drive the 6 LCDs. That would go hand-in-hand with a keymapper input API the likes of which already exist as 3rd party utilities.
