But as has been pointed out many times here this summer, the technology to make ethanol on a massive scale as you describe does not exist.
Several companies across the world have spent hundreds of millions trying to and all of them have failed.
And yes I have worked on a farm. So what?
That has no impact on the discussion of them using food, corn and cane sugar, for fuel. I would love to see cellulosic ethanol pan out, but so far it is a dud.
http://www.smartplanet.com/blog/smart-takes/the-morning-briefing-biofuels/28558 It has been such a failure that now the EPA is set to approve yet another food stock, grain sorghum, for use.
http://lubbockonline.com/agriculture/2012-08-19/epa-approve-grain-sorghum-cleaner-ethanol#.UDR_nt1lR6g 
