I''m not sure about the voltage, but I''ve seen a lot of comments by people who used the little fans from computer power supplies. May want to look into that, would seem to be the right size for what you want.
You might want to run a yahoo search on KISS wind generators...because you should get a link to "Hotwire"...they are in St. Pete FL area and besides the KISS wind generators they sell a port mounted small computer power supply kind of fan that moves quite a bit of air. I saw these fans at the St. Pete Boat Show recently and they do move a pretty good bit of air. Send an email to them - address it to "Libby".
If you can''t find a link to them, email me at [email protected] and I''ll hunt up the email address for you.