Corn produces some protein and some oil, which don't get turned into ethanol. Reasonable corn yields require huge amounts of fertilizer, which requires a lot of energy to produce.  Harvesting corn in the US is fairly energy-intensive also.

Sugarcane, on the other hand, produces carbohydrates with very little protein or fat, with less fertilizer input, and it is harvested with fewer energy inputs as well, at least in Brazil.

So while you may well be correct that the Brazilian numbers are inadequately documented, I don't think it is hard to believe that one crop might be vastly superior to another by this metric (EROEI) for ethanol production.

I find it difficult to believe that one particular woody plant (sugar cane) growing on this planet earth and receiving similar solar radiation could be 4X as productive as corn, soy, etc. converting said radiation to similar mass.

I admit I'm a skeptic too, but then I also readily admit I'm not a biologist of biofuels expert, hence the "(Maybe)" I appended to my statement about Brazilian sugar cane.  But sugar cane in relation to US demand is inconsequential, as A) we can't grow sugar cane like the Brazilians can, and B) Even if we could, several people have stated we would still need to curb our appetite for liquid fuels as it can't replace current oil consumption.  

So we are left with Corn, which currently is in the middle of a firestorm of debate about its viability.  Not saying we shouldn't explore corn ethanol at all, but pending our futures on an untested "maybe" doesn't seem smart to me, when we do know of models which could allow us to maintain a modern standard of living albeit a different looking one.  Mainly accomplished by bussing/trolley systems, light rail, heavy rail, and an effort to bolster and improve our electricity grid along with localizing electricity generation via solar, wind,