Here are the 2005 ACU Ratings for the various RINOs:
SNOWE 32
COLLINS 32
Landrieu 44
DeWINE 56
SMITH 58
Nelson 60
SPECTER 63
COLEMAN 64
VOINOVICH 68
GREGG 72
STEVENS 80
McCAIN 80
HAGEL 96
GRAHAM 96
MARTINEZ 100
Coleman (who I happen to think is not a bad Senator for Minnesota at present) and Specter are basically even and both come from Purple states. Specter is just more visible. DeWine ACU rating for 2005 is lower than Specter so I don't see how you can call Specter a RINO and not DeWine.
I am in agreement with most of what you have posted, with a few exceptions: I think Laffey has very little chance in RI if he beats Chafee.
First of all, DeWine's career ACU score is an 80, while Specter's is a 45. That's something to think about.
Second, the ACU is not the only entity that rates members of Congress; I don't think a complete analysis would exclude ratings by the liberal ADA, AFS (labor) or LCV (environmentalists) or the conservative NTLC (taxes) or Christian Coalition. Michael Barone lists the ratings from the 5 groups I mentioned, along with the ACU and a couple of other organizations whose ratings I don't find quite as useful. What I do is add up the ratings by the 3 liberal groups and subtracted the score from 300 to get a conservative score, then I add up the ratings for the 3 conservative groups, so each Senator can get a maximum of 600 conservative points. For the 108th Congress (2003-2004), I assumed that the NTLC and Christian Coalition scores were the same for both years, since those organizations rate members of Congress over a 2-year period. For 2003-2004, Mike DeWine got 506.5 conservative points, or 84.42% of the possible conservative points; Arlen Specter, despite voting much more conservative than usual because he knew he would face a strong primary challenge from the right, got 435 conservative points, 72.50% of all possible conservative points. Lincoln Chafee got only 45.92% of conservative points, less than Democrat Ben Nelson (49.58%). Norm Coleman got 87.83% of conservative points, a tad higher than North Carolina's Liddy Dole and far outside of the RINO range. The biggest surprise I found was that McCain's move to the left, especially on environmental issues (he got an average of 60 points from the LCV), left him with 69.33% of conservative points, which was actually lower than Specter.