The high price of cellulosic biofuels from cellulose, corn stalks basically, is some way off. This story from Reuters and found on Planet Ark explains why, and why it may not be such a good thing for farmers or food production. Quoting from the report:
The US Department of Energy has estimated the cost of producing a gallon of cellulosic ethanol is about US$2.20 per gallon, about twice the cost of producing ethanol from corn.
Farmers have a narrow window to harvest corn for grain. A second harvest to cut stalks and leaves would not only take more time but could hurt future yield potential by compacting soils and removing potential nutrients