The FAA is still having a tough time coming up with rules and regulations for commercial (and agricultural) use of Unmanned Aerial Vehicles (UAVs). Recent news is that one entity has been given some degree of approval for commercial use of a UAV for crop scouting.
Current regulations would allow for a tethered (tied to the ground) device as long as it doesn't exceed a height of 150'. Under this height, it could operate autonomously, and even continuously if desired. There may be a market out there for such a device for agricultural use.
