What if X and D's separation during the Terror leads de Sade to entrust X with an estate...and he keeps up with the friendship post everyone becoming a Citizen, and somehow X manages to pose as a cousin de Sade, who keeps the estate until roughly WWII-mid 1950's, selling documents that he "found" for cash to get out of France?
more on this later...as I have to get dressed, pack, and then take off to the train station to get to Pacifica asap. :D woot! Happy Labor Day!