I had an idea for a dev board that would be built into a tablet, with the ability to program an onboard microcontroller and also just use a simple interface to control individual outputs. So imagine being out on site somewhere, and you need to check a circuit, or some code; you would simply use a pinout on the tablet to interface with the system, and be able to both program a code fix, and check circuitry. For added complexity, you could even include a built in multimeter and/or oscilloscope!