I think you are correct. Once the Iraqi Constitution and new government are in place in January 2006 there will be a huge push by Shiite and Sunni leaders for a fast withdrawal of Coalition forces. It will be less intense from the Kurds but they will probably want us out as well so they can begin to emigrate back into traditional Kurdish areas like Kirkuk (leading to some violence with the Sunnis there). I predict most Coalition forces will be out of Iraq by the end of next year whether their security forces are completely ready or not.
There won't be a push for us to leave until the Iraqi government has faith in their own troops.