Jim,

You ought to check with DMV about the possibility of gettting an exemption
based on the use of alternative fuels.

You can find links for the California DMV inmy DMV resource page. There are
links there for all the DMV's in US. IIRC there should be an EPA and DOT link
there somewhere too. (i'm too lazy to check obviously).

See:

http://members.aol.com/bentbtstr8/vanagoncafedmvreourcepages.html

BenT