I am trying to verify that an ancestor of mine, who was a personal representative of the Sovereign and acting out the duties of Canada's Keeper of Customs for (Quebec and Ontario) Between the years of 1820 1830. Are there any government or private resources that contain information about who was the head customs officer for this period for Quebec and Ontario? The individual’s name was Sir Richard Cross.

Probably! As Canada was not yet a country you might find these records are kept in England (see the UK National Archives: http://www.nationalarchives.gov.uk)