Mike T,
I just wanted to add that Mike Kelner has microfilms of all the original p-51 prints from the factory. He didnt get them from the Smithsonian. These are from North American.
Mike, You can also check out "Tri-State Aviation". There are happy to assist with your project and custom manufacture components you might need. Cindy Beck is the owner and seems like a nice person that will work with you. She is the widow of Gerry Beck. Also, you might want to try to contact...