To say that MI could go republican is like saying that Illinois could go republican. Both states were a win for Daddy Bush, and been Dem ever since. MI has more republicans at the state level due to gerrymandering, but republicans are in a slump as far as anything statewide. We have republicans on the state level who go to Lansing with only a fraction of the number of votes a Democrat receives in another disrict. I forgot exactly what the numbers were, but Democrats won far more votes than republican in '06 for State Senate, but the Republicans are still in charge of that chamber.
This is a waste of time, but:
Michigan was close in 2000, 2002, and 2004. Illinois almost went to Dukakis in 1988 and has been more and more Democrat ever since. There can be no comparison.
I don't believe for a second that MI will be a blowout either way. I think it sitting on the Dem side of the fence, but it wouldn't take very much to push them over. I actually think PA is solidifying for the Dems, and OH remains the trickly little bastard it has been for the last God knows how long.
My belief is that with the Bush factor gone, MO, TX and AR becoming more competitive. Not that I think a Dem will win any (maybe MO).