steve - often the best resource for locale-specific photogrpahers is your state historical society/museum, and even some of thelarger county historical societies. there are many very fine books that deal with 19th century photography and practitioners, but they generally focus on a few principal and more well-known photogrphers. there are also some large-scale collectors out there that have quite a bit on knowledge about this subject. if there are a few specific folks you have in mind, give us the names, and we can check the references we have - i maintain a large library of materials on early photographers, and may be able to help you somewhat.