The most tiny autopilot in the world was introduced yesterday by the Technical University of Delft, The Netherlands.
Named Lisa/s, she comes in at the scales with just a mere 1.9 grams, the 2*2 cm board has everything that a multirotor needs. Among the sensors are a 3 axle gyroscope, compass, barometer and a gps module. It also includes Superbitrf, which allows it to be in contact with a groundstation and a rc controller at the same time.
It runs on Paparazzi and will go on sale via 1bitsquared in January 2014.
More info (in dutch) here and a video: