In the light of the recent FAA registration limits, the great guys at sUAS News wrote an article featuring the Paparazzi UAV powered Lisa/S nano Quadcopter. This platform was developed by 1BitSquared in collaboration with the TU-Delft MAV lab team, provides all the autonomous capabilities while being way below the FAA regulated limits for registration. The Lisa/S nano Quadcopter weighs only 39g while the FAA requires all aircraft above 250g to be registred.

Check out their article for more information.