In anthropology, the study of peoples and their cultures, the researchers write up an essay with their data at the end of a project. These are called ethnographies. Within these books is a great deal of variation, but the ones that deal with whole cultures (not sub- or sub-sub-cultures) almost always have a chapter on child-rearing styles.
Here are sites that list ethnographies, some classics and some new studies that have really branched out from the original form:
http://www.powells.com/subsection/AnthropologyEthnographies.html
http://members.tripod.com/anneballenger/anthro/ethlist.html
These are some classic ethnographies that may be useful:
Title: Life among the Yanomami : the story of change among the Xilixana on the Mucajai River in Brazil /
Author: Peters, John F. (John Fred), 1935-
Call: LIB SHELVES F 252.1 Y3 P48 1998
Title: The Australian aborigines,
Author: Elkin, A. P. (Adolphus Peter), 1891-1979.
Call: LIB SHELVES DU120.E4 1964
Title: The Tiwi of North Australia.
Author: Hart, C.W.M. (Charles William Merton), 1905 -
Call: LIB SHELVES DU122.T5 .H3
Title: The Dobe !Kung /
Author: Lee, Richard B.
Call: LIB SHELVES DT797.L42 1984
Ethnographies will give you data, to crunch it you'll need to use your noggin.