I don't envision a guerilla war in Iraq afterward. Sectarian violence between Sunni and Shi'te- and ethnic violence will most certianly occur and heavily at first but it will tapper off to low level intensity. But much of the terrain is not conducive to such warfare. But I do envision frequent terrorist attacks on troops stationed there for decades to come in the form of suicide bombers and traditional bombs at nightclubs, hotels- or any places Americans gather. But even that may not occur that frequently if we adopt the approach we seem to have in Kosovo and Bosnia- large fortress like bases- not near significant population centers- with patrols being conducted in force with gunship support. As has been noted- this approach certianly keeps our troops safe but has been innefective in establishing anything like law and order in Kosovo and Bosnia where ethnic violence and lawlessness are still endemic- just fought at lower levels of intensity so as not to arouse the Empire into action. Iraq will be pretty much reduced to the same thing- rule of thug and local warlord with a veneer of a "democratic" government that controls pretty much nothing outside of the government buildings in which they reside.
We will be there for decades to come and Iraq is only the first country in that region we plan on bringing "democracy" too.
You make a good case with your nuanced analyis.