If you do email anyone, would you also ask 'em who, if anyone, owns the copyright to Bell's photography? As near as I can tell *SOME* of his work resides in the National Anthropological Archives
http://www.nmnh.si.edu/naa/guide/_b2.htm but some may be in the Library of Congress. (or are they the same?)
I was wondering that, too. There also seems to be some in the Keogler collection.