I don't know. Considering that Kerry could have very probably won the 2004 election without winning Missouri, the same situation could very likely happen in 2008 as well and it would lose it's status.
That's not the point. A lot of other peopel could have one the race without Missouri. Missouri simply tends to side with the winner. As Missoui goes, so goes the rest of America. Missouri also has a tendency to overstate the majority of the winning candidate, which I would say acctually improves it's status as a bellewether, because it will swing more than a lot of other states to hand its EV's to the winning candidate.
I too have noticed the potential of using the MIMIL states in presidential races. In fact, an alternative primary proposal that I once drew up proposed that, rather than simply have Iowa go first, the MIMAL states should all go first on the same day, thus obtaining a better idea of what voters all over America really want.