26 Oct 07 update of the CSIS report originally posted near the beginning of this thread:

Pandora’s Box: Iraqi Federalism, Separatism, “Hard” Partitioning and US Policy
The attached report provides a major revision of the previous draft report on the prospects for federalism, separation, and partition in Iraq, and is virtually a new document. It has no simple bottom line, and all of the options present agonizing trade-offs and are almost certain to resul in some degree of added separation and displacement.

At the same time, the analysis indicates that the vast majority of Iraqis -- other than Kurds – do not want a weak central government or any form of division of the country. It shows that violence is serious in the areas dominated by the Kurds, Sunnis, and Shi’ite as well as in mixed areas, and that any form of federalism or partition that divided Iraq’s economy, infrastructure, and petroleum sector would be almost impossible to achieve on anything close to an equitable basis or using Iraq’s present governorates and divisions by sect and ethnicity.....