I almost wish I had not started this thread as now I have googled "quadcopter" and I am hooked, totally hooked!......
Indeed! Fires the imagination right up, doesn't it?
Regarding various restrictive or/and prohibitive laws, I read somewhere that one way around such laws is to tether the craft to the ground as the craft is no longer 'unmanned'.
Of course a tether will add weight, the lifting capacity of the craft will need to be increased to compensate.
And, obviously, the totally free flying capabilities will be greatly reduced.
Still, even tethered close, many creative possibilities remain within the unusual perspectives still possible.
The actual tether could be as simple as kite string (oops, string broke, it got away, sorry officer) or how about CAT5 cable for tethered control of the camera to a PC?
I can think of many applications where a tether would be undesirable, such as outdoor athletic events like foot/bicycle races and the like, how cool would that be to follow the leaders along a course?
Still, if local laws prohibit such use, work within those laws, best possible.