This looks like a fun project.
[url]http://geekbeat.tv/crazyflie-quadrocopter-youll-believe-a-circuit-board-can-fly/[/url]
If I’m right this project has come by already 
I like how they built a PCB which functions as chassis.
And the best is you do not need to build a chassis and even better your electronics are very ordered and you do not have wires everywhere ;D