The main knock I have against diesel is that it's readily available...globally. I'm no petro-engineer, but I think that diesel is the by-product in the making of gasoline. We use gas in the States, whereas most of the rest of the world uses diesel*. What would happen to the world's petrol supplies if we switched lock, stock, and barrel to diesel? E-85 is not the answer. These gas/electric hybrids aren't the most ideal, either. Diesel/electric would give you way more MPG.

Around here, CNG is an option. Local natural gas company has fueling stations available to the public, not just fleet customers. I've seen info about CNG kits that would allow you to top off the tank overnight off your home's gas line. The main drawback is that they are a dedicated system, so you really have to keep an eye on your fuel tank, and plan your route accordingly.

*Brazil is burning fuel based on sugar.

Aw, crap, y'all got worked about cars on a bike forum. I feel so dirty. Must cleanse the cycling spirit by looking at bike prOn.