This is from a post at www.redstate.org. But I like your scnenario a lot better!
...On to the Senate. Due to real world commitments, I haven't done a round-up of the Senate in many months. And again, I don't have the time to analyze and present each major race right now. Fortunately, the National Journal's Chuck Todd (subscription required) has his latest rankings out on the Senate races. They are below the fold with some commentary.
Here are my commentless rankings.
Most likely to change from D to R:
1. Minnesota (Open)
2. Maryland (Open)
3. New Jersey (Open if Corzine wins for GOV)
4. Washington (Cantwell)
5. Michigan (Stabenow)
6. Florida (Nelson)
7. Nebraska (Nelson)
8. West Virginia (Byrd)
Most likely to change from R to D:
1. Pennsylvania (Santorum)
2. Ohio (DeWine)
3. Rhode Island (Chafee)
4. Missouri (Talent)
5. Tennessee (Open)
6. Montana (Burns)
7. Arizona (Kyl)
8. Mississippi (Open if Lott retires, if not forget about MS)
Mr. Todd and I obviously disagree on parts of the ordering of vulnerability of seats. Considering the buzz around 2006, Rs are actually in better shape than the conventional wisdom has them. Only one incumbent lost in 2004 (Daschle) and Rs are only defending one open seat so far (TN). Most races are in states carried by the President. Rs lucked out by having concensus strong candidates in the 3 open seats at the top of the list (MD, NJ, and MN). Rs missed several opportunities in friendly states due to recruitment problems. Nevertheless, the line-up actually looks like a wash overall. If the races were today, PA and MN would flip sides and MD would be close. No other changes. But we have a year to go and if the tide flows strongly one way or the other, a +4 for either side is not unreasonable.