The IG report released today requests a special prosecutor to continue the work of the investigation into whether the nine U.S. attorneys removed in 2006 were fired for partisan political reasons.

From page 357 and 358 of the IG report:

The most serious allegation that we were not able to fully investigate related to the removal of David Iglesias, the U.S. Attorney for New Mexico, and the allegation that he was removed to influence voter fraud and public corruption prosecutions. We recommend that a counsel specially appointed by the Attorney General assess the facts we have uncovered, work with us to conduct further investigation, and ultimately determine whether the evidence demonstrates that any criminal offense was committed with regard to the removal of Iglesias or any other U.S. Attorney, or the testimony of any witness related to the U.S. Attorney removals.

Late update: The report also describes the stonewalling the investigation received in trying to gather information on the removals. Specifically, it mentions a "fact memo" created for Alberto Gonzales by the DOJ's Office of Legal Counsel, which outlined the events chronologically, using a draft written by Michael Scudder, associate White House Counsel. Investigators were refused the timeline by the OLC who claimed they were ordered not to release it by the White House Counsel's office.

From page 94 of the report:

We asked OLC for a copy of the memorandum and all the drafts, but OLC declined, stating that the White House Counsel's Office had directed OLC not to provide them to us. We thereafter engaged in discussions with the White House Counsel's Office during this investigation in an attempt to obtain the Scudder memorandum. The White House Counsel's Office agreed to read one paragraph of the memorandum to us, and provided us with two paragraphs of information concerning Rove that had already been reported publicly, but declined to provide any further information from the memorandum.
Eventually, the White House Counsel's Office provided us with a heavily redacted version of the document. We believe the refusal to provide us with an unredacted copy of this document hampered our investigation.