http://www.ariannaonline.com/columns/column.php?id=63 gives a hint at it:
"Will the deaths number in the hundreds, as was the case in Desert Storm and as would be again if Saddam collapsed like a cheap umbrella? Or will they be closer to the 10,000 to 50,000 some experts have predicted? And is Saddam the clear and present danger that would justify asking our sons and daughters to give up their lives for their country?"
I think 3k or so was the usual number bandied about, at least it's the one I remember. But that was for the 'cakewalk' that the media decided it should be and derided when the troops got bogged down in the extended quagmire that was the seige of Baghdad, not the insurgency that wasn't expected widely. It's one thing to say that there were those that were right on any given point, but another to say that those were the one's judged most likely to be right by most people at the time. Those that were right didn't get much airplay, or taken seriously. That frequently happens.
The plan was also that it would take longer than it did to see Baghdad fall, that they'd attack through Turkey, and that many 100k refugees would go streaming across the border, that the Iraqi army and bureaucracy would be preserved intact. The UN set up large refugee camps that were closed a few months later when virtually nobody showed up.
So much for plans. And projections.