I'm assembling a history of American signpainting book for my typography class and am looking for hi resolution images of signs and signpainters throughout history for use in the book. I have done countless google and flickr searches, but some of the best stuff I've found ( http://theletterheads.com/lhparts/atkinsonmain.html http://theletterheads.com/lhparts/halsted.html http://typography.com/images/blogImages/berenice-abbott.jpg http://typography.com/images/blogImages/drawing_office.jpg) are just not high enough quality.

Any ideas on where to get some premium quality signpainting images?

Thanks in advance. You guys are the best.