I definitely agree that producing biofuels from food crops is not an economically, socially, or environmentally sound strategy. I personally believe that producing ethanol from cellulose in weeds (e.g. switchgrass or fast growing trees) is probably the most viable biofuel production strategy, but the technology to efficiently create ethanol from cellulose is not here yet.
What's the advantage of hemp? It doesn't seem like it would produce enough starch for conventional ethanol production, so it seems like it would be a cellulosic feedstock. However, for cellulosic ethanol, most of the stuff I've seen has promoted other fast growing plants.
Also, what's the advantage of butanol over ethanol? I keep hearing people promoting ethanol, but given how much easier it is to produce ethanol than butanol, I'm curious as to why people believe butanol to be a better fuel.