One of our growers out in Central Illinois turned a field into an "Abe Lincoln" corn maze for the tourist trade this year. They drew a bust of Lincoln with AgLeader GIS software, and fed the result into a navigation file for their GPS equipment mounted on a four-wheeler with a spray rig. They killed the (non-Roundup Ready) corn with a Roundup application, and then mowed the results. I've got a dead trees newsletter with a photograph of the results; can't find anything online about it yet, sorry...