As it happens, one of the leaders in this area of research is a faculty member here in the Chemical Engineering Department at OSU. When I posed the requester's question to Prof. Bhavik Bakshi, he responded...

"This is an area where we have done quite a bit of work lately, as have others.  I have attached a paper that contains some of our findings. Corn ethanol can save oil and some CO2 (if you ignore international land use changes), but it uses more of almost every other resource.  If land use changes are considered, the greenhouse gas benefits could be reversed."