I want a helicopter...

Further to my last post on using quad-rotors/any-kind-of-rotors as pixels in a 3D screen, I've just seen this;

There's talk of apparently using these to patrol Queensland beaches for sharks and to drop life-preservers to people in trouble (since they can carry around 7kg). 
It's gotten me thinking, how difficult would it actually be to put something like this together from scratch? Presumably fairly difficult since these sorts of things are being commercialised all the time.
But similarly, there must be a software package out there that you could use to run some sort of rotor based flying device? You wouldn't need to use some sort of embedded system, surely you could drop it onto a rasberry-pi or an arduino?

Anyone got any ideas on the matter?

In unrelated news there's some suggestion that it might be possible to make an Alcubierre drive with a reasonable power demand (rather than the previous estimate of 3 times the output of the sun...). So that's pretty fucking exciting!