Here's a rough blueprint...
After NH, I think the top three will still be hanging around ( Newt, Cain, Mitt). If Perry turns his camping around..it will be a 4 way race. Paul will be there..with between 5-10%..he'll stay till near the end..because he has $$..and his supporters are fanatical.. the second tier..Bachman, Santorum, Huntsman..with between 10-15% fo the vote combined..will have to drop out..no funds..and we'll see where their vote goes. If most flows to ONE candidate, it can be decisive..if it's spread around.. we continue..
My personal feeling is that Mitt's done after NH...he's gonna do 4th in Iowa..will only get a small plurality in NH, and will get wiped out in SC..I think you come down to Perry, Newt, and Cain..all with about 20-25% of the vote, some for Paul, and most undecided..if the following primaries, including Super Tuesday..aren't decisive...then we can come to Tampa with 3 in congtention..though obviosu that not ONE of them is the favorite...or can even command a majority..
After that..it's anyone's guess?
I picture things a bit different than you.
Iowa Newt and Cain statistically tied. Perry a distant third, followed Paul. Bachman might even beat Romney.
N.H. - Romney wins minimally.
S.C. - Cain, Newt, Romney, Perry.
FL. - This is hardest to predict right now, but will also be the one that starts driving candidates out. My gut feeling is that Cain has an advantage over Gingrich here, but that might be wishful thinking on my part. This could be the spot Romney bails out again.