I found a very humorous book on privies with great illustrations, photos, plans, and cartoons.
Barlow, Ronald S.
2000 The Vanishing American Outhouse: Privy Plans, Photographs, Poems, and Folklore. Viking Studio, New York.
Stacy Schneyder
Cultural Resources
Jones & Stokes
2600 V Street
Sacramento, CA 95818
916/737/3000