I just viewed a document that had been translated from Russian into English, sort of, for my husband's father's family. The name Przybyszewski came up as a witness, so I thought anyone with an interest in this surname might want to see this. Here is, basically, an outline translation:
...Bith and baptismal certificate for Adam Niedzwiecki from village of POPOWO, Parish GRAJEWO.
Father: Jan Niedzwiecki, 31 y. old, worker in Popowo
Mother: Rozalia, 30 y. old
Date of birth: 27 August 1881
Baptism: 30 August 1881
Witnesses: STANISLAW PRZYBYSZEWSKI, church servant and Szymon Skorzynski, peasant
Godparents: Jan Godlewski and Janina Gorska
That's pretty much it, but at least you have the general area from which at least one Przybyszewski came from.