A quick look in wikipedia at the entry for butanol and the section on "production" and the link there is informative. Butanol can be used in any car, doesn't need "flex fuel" tech, and be mixed with gasoline in pipelines, and can use the standard infrastructure in place.
Production can be from corn stalks and other plant biomass which currently do not generate revenue. The factors of choice are economic and political, not necessarily technical.
It would be nice if energy policy was not related to the cost of brewing, but it really is.