Found one Lederer who was a "viner" in Al Sas Lorraine, France near the German border.
This sounds correct by the family oral history.
The Lederer's were into growing grapes for wine.
The family went German as the Germans were Lutheran as opposed to France who went Catholic.
Found some Lederer's from the same town as Martin Luther came from in Germany.
I have also been looking for Lederer relatives. I have to dig up all my research, as I moved recently and it's still packed away in a box somewhere. But I have actually been thru your great grandmother's house and even spent the weekend there, as it is now a bed and breakfast. Unfortunately it has been totally renevated, so it doesn't look much like it did inside or out. I believe, and this is just off the top of my head, that your great grandmother was my great grandfather's sister. Would love to share any information with you that I have and discuss any you have as well. If you would feel comfortable calling me, my cell phone number is 920-331-7221, home number is 920-449-5949 and my regular e-mail address is email@example.com. Look forward to hearing from you.
P.S. One of the stories I have heard about your great grandmother is that after the crops were harvested, she would hang a red blanket out her window to let everyone know it was time to come for a celebration.