Dell Venue Pro 8 (8" Win8 tablet) with a Zagg auto-fit 8" keyboard. Obviously not optimal, but works for most purposes with some rejiggering. Necessary addons: Dell's Micro USB dongle for data and charging. Vaguely pricing this right now, you're looking at $250 if you buy the tablet used on Amzn.
Fastening tape (high-test velcro) on the back of the keyboard case means you can carry it all as one modular unit, attaching and detaching what you need at will. Go that route and you'll need to add a kickstand on the back to keep the rig from falling over backwards.
Probably going to replace it with an RPi-2 based system eventually.
