I am also a descendant of Johann and Maria. I found an early census that shows that Johann was from Damstadt, Germany. That is the earliest confirmed information I have. Do you have any earlier inforamtion? Have you posted your family tree to Ancestory.com?
Regina Drott Foreman (daughter of Allen; son of William Henry; son of Adam; son of Johann)
my e-mail address is regfore@comcast.net