Along those lines, the Energy Blog had posts for a couple of exotic-sounding alternative fuel possibilities that I hadn't read about before. One is a cellulosic ethanol energy crop called miscanthus, whose output exceeds that of switchgrass:
In the 2004 trials, miscanthus out-performed switchgrass by more than double and in the 2005 trials more than triple.(Don't know if that means the amount of crop produced, or the amount of energy produced.) And the other is jatropha, a biodiesel crop which grows well in undeveloped land:
Although not suitable for temperate climates, jatropha promises to be less expensive and less competitive for land than food based oil seeds that are used as feedstock for biodiesel.