Here are three links you can try, if you haven't done so already.
English-America: The Voyages, Vessels, People, & Placeshttp://english-america.com/
(English-America recommended by Family Tree magazine)
Finding Passenger Lists Before 1820http://home.att.net/~wee-monster/1820.html#virginia
If these don't help, contact the reference department of your local library or university for their recommendations and suggestions.