"How much worse things in Iraq would be now if the US forces had simply stopped after wiping out Saddam and just left. Keep as much of the bureaucracy (the part that actually does the work of running the country) intact, same with the bulk of the armed forces - again, the ones that actually do the work. Give a grant of 10 billion to the government, to be held by Switzerland or someone until there is a recognized election."

Well maybe it's good idea. But we didn't "wipe out" Saddam until about a month ago. But let'snot deal with having court trial and all that. Let's say we simply captured him and put in an American prison [though that could be a problem- I'm guessing that is illegel in terms of international law and of course he is not a US citizen. Now, if you think we should have simply put a bullet in this head when we captured him- that would have made things easier].
But more importantly a serious problem to your plan is we captured Saddam much later than completing invasion: "The former Iraqi dictator was captured Saturday at 8:30 p.m".
http://www.foxnews.com/story/0,2933,105706,00.html
So he was captured saturday Dec 13 2003. And "Saddam has been on the run since the fall of Baghdad to U.S. forces on April 9." That's April 9 2003.
It took *only* 3 years to execute him- if he had been in the US he wouldn't have been executed, nor would the trial have even begun by this time.

There are other problems to your plan. First, how many Iraqis would die from starvation and disease? As a result your course of action? Why would Iraqis stay in Iraq? What would other countries like Turkey and Iran do? Another aspect is I believe there is international law that obligates an invading force, to establish law and order, and do things that allow a goverment to form in a timely manner.