Hey,
My personal preference would be to build a single rotor helicopter instead: I think they are simpler to maintain. Also, if you want to get into UAVs you'll probably need to learn how to fly them first (unless you already know). Its usually a good idea to buy something like the V911 Heli, or a similar grade quad-copter to practice. I also suggest a decent sim too so you can practice even more. Did I say you need to practice?
just be careful about advertising unsupervised operation of any UAV on public boards, as it could potentially lead to the FAA finding out and you could get in trouble. While unlikely, it is worth mentioning. Also, don't even consider arming your multi/heli UAV... people might not like to see an armed UAV equipped with night vision and FLIRs floating around their property; I know, its really cool, and its probably been done; but if the thing has a problem, you (or someone) could potentially get shot (and killed). AMA (and their supporters) might not see that well and state that you always need to have a human pilot behind the controls.
If you're interested in knowing more, let me know.
G.