I know you said you weren't looking for this, but, hey, someone else might be.
Bush got onto the subject in response to a mention of Somalia, and said:
"Started off as a humanitarian mission and it changed into a nation-building mission, and that's where the mission went wrong. The mission was changed. And as a result, our nation paid a price. And so I don't think our troops ought to be used for what's called nation-building. I think our troops ought to be used to fight and win war. I think our troops ought to be used to help overthrow the dictator when it's in our best interests. But in this case it was a nation-building exercise, and same with Haiti. I wouldn't have supported either." Link:
http://www.debates.org/pages/trans2000b.htmlAs for "liberating or freeing the people of Iraq", I think that idea was actually mentioned, although it wasn't nearly so prominent as the scare-mongering about WMD's and al-Qaeda. As an indirect source on the Bush Administration's pre-war statements, I found a 2004 report from Human Rights Watch that used these terms in characterizing the pro-invasion rationale:
"(T)he United States-led coalition forces justified the invasion of Iraq on a variety of grounds, only one of which—a comparatively minor one—was humanitarian. ...
....
"A humanitarian rationale was occasionally offered for the war, but it was so plainly subsidiary to other reasons that (Human Rights Watch) felt no need to address it. Indeed, if Saddam Hussein had been overthrown and the issue of weapons of mass destruction reliably dealt with, there clearly would have been no war, even if the successor government were just as repressive. ...
"Over time, the principal justifications originally given for the Iraq war lost much of their force. More than seven months after the declared end of major hostilities, weapons of mass destruction have not been found. No significant prewar link between Saddam Hussein and international terrorism has been discovered. The difficulty of establishing stable institutions in Iraq is making the country an increasingly unlikely staging ground for promoting democracy in the Middle East. As time elapses, the Bush administration’s dominant remaining justification for the war is that Saddam Hussein was a tyrant who deserved to be overthrown—an argument of humanitarian intervention. The administration is now citing this rationale not simply as a side benefit of the war but also as a prime justification for it. Other reasons are still regularly mentioned, but the humanitarian one has gained prominence."
Link:
http://hrw.org/wr2k4/3.htm#_Toc58744952Based on those comments by HRW, my guess is that you won't find the kind of clear-cut contradiction that you're looking for. Instead, there's been a shift of emphasis.