Interesting application for drones... and farmers (unintuitively, maybe) are big developers and users of technology. Farmers were using GPS technology in the early 90's (in combination with other, existing 'yield calculation' methods) before there were enough NAVSTAR satellites to make it work all the time. Early adopters had to know the terrestrial paths of the existing satellites so they could run their GPS units when there were enough of them in the sky at once to return accurate data.
But one problem I see with the theory of integrators selling these to farmers is that farmers have distribution channels just like physical security does. They are a very insular bunch - in general.
Way back in the day, I worked for a publisher that did monthly state-based, and quarterly vertical-based agricultural magazines. When the original GPS farming applications were coming out, I sold ad space in our pubs - and I got them to run ads across our spectrum of magazines. And they got little direct response. This did not make them happy, as I had painted them a rosy picture of their phones ringing off the hook the day after our mags hit the streets (or the farms in this instance).
The ads did provoke phone calls to agricultural distributors (also customers of mine) asking about this new technology. It wasn't until these manufacturers partnered with established agricultural distribution channels that their sales took off.
So maybe, if Anixter, ADI and ScanSource started carrying drones, integrators would sell them.
NOTE: The above relies on old knowledge of farming applications. Farmers quite possibly rely less on their distribution channels now that the internet exists than they did back then (kinda like physec)...