How about those hand pumps that you see on the portable tanks that farmers and landscapers have in the back of their pickup trucks.
Would they have the lift necessary to pull gas out of the bottom of a buried tank?
I know if the tank level is below 14.5 feet (standard atmospheric pressure) no pump will pull it up.
Atmospheric pressure is 14.69 psia. This equates to a best of about 28 feet of suction lift with water. Would be less for gasoline but a good NON-Sparking hand pump would do the job, IMHO.