I also work designing processor intensive software, so I'm aware of the limitations of computers. And I've done weeding on farms - distinguishing Italian ryegrass from perennial ryegrass for example. That's why this whole robot idea excites me.
if you know its comming , then you could start it.
if its something you like , then its not really work.
you seem to know how its done and the web based application
you mentioned would be a great idea as the cloud could perform the computations.
every farmer could allow a percentage of there processing capabilities to be used by the cloud , and you can build
the cloud yourself in an application that is downloaded and installed on the farmers computers.
there is probably plenty of funding available for something as this.
try the go big network , and remember that Microsoft has the biz spark program where you have access to every program that Microsoft sells.