There is the HUNTER RQ-5A (used by US Army, USMC, France, and Belguim)and will fly as high as 20000 ft. they use the Global Hawk. they use the predator. they also have some smaller ones either in use or under devlopment.
the new ones are very small and quiet and very difficult to kill. mt no 1 argument is uav's are to easy to kill.
http://www.army-technology.com/projects/hunter/
http://www.af.mil/factsheets/factsheet.asp?fsID=175
http://www.airforce-technology.com/projects/predator/
http://www.vectorsite.net/twuav08.html