@marlinspiker--do you home brew? Where I buy BD, the price pretty much mirrors the #2 petrol prices and always costs more. For awhile during the last price spike they were competitive, but at times BD is as much as a dollar more per gallon.
Of course, every niche market is going to be high, and I keep buying BD so I don't have to support the petroleum companies. Maybe you weren't even suggesting it might be cheaper, but only that it's a better choice. I agree with that completely.
As for $5/gal--as a business owner, that scares me. As a resident of planet earth, I say that's still too cheap. Petroleum should be disincentivized to encourage more development of alternatives. Anyone notice how popular the new electric cars have become in the climate of expensive fuel (and they don't really cost much more than a new gasser)?