Helmut,
- I sent a message w/ your needs and contact info to a guy I've had a few deals w/ in the past and I believe is an hour or so away from Ossipee..
He's a nice fella and director of the NH State Snowmobile Museum also I think may have a few vintage signs himself so could be a good guy to have on the other end if he's close enough and has the time to help!.
Sounds like a cool sign...Texaco star?.
Pics?.
Good luck!.

~ Pete