Here's an article on yahoo's auto page -- there are some interesting vehicles there, plus some technological tidbits. Not much a mortal being can, or want to buy right now, however.
http://autos.yahoo.com/green_center-article_161/

 

http://www.memagazine.org/mepower03/...g/gauging.html

 

Several problems.

First, there's only one vehicle there (Honda) that was obviously using hydrogen. The rest appeared to be using batteries, though in some cases that was only implied.

The next one is that the article doesn't tell much about how they were getting their numbers. Did they just pull them out of thin air? Probably not, but I have a feeling they had to make several assumptions that may or may not be correct (like H2 is made with, or from a fossil fuel); however, without a more detailed writeup and some background info (who paid for it, for instance) it is difficult to judge the correctness of their numbers. One would need to look up the original article, and possible the follow-ups it may have generated in the "Transportation Quarterly".

Lastly, all that is based on information available up until 2002. Since then, we've had a significant oil price increase, and a little over 4 years to work on alternatives to gasoline and diesel. If nothing else, the increased oil price should have some effect on the economics of alternative fuels.