I tried to be as much of a Republican as possible. In other words, ignore communities of interest or any in-state redistricting "rules" in order to maximize the possibility for some gains. In the end, I don't end up with any districts that are a sure thing for Republicans but they have a good shot in a neutral environment at two seats, and two more seats in a favorable environment. Also, while Republicans have a tendency in most places to nominate the most unelectable candidate, there's not much history of this among Republicans in Massachusetts.
2008 Obama/McCain: 52.7%/45.1%
Dem Avg: 39.2%
The first Republican opportunity district takes in some of the most conservative areas of the state.
Green, 2nd: Springfield, Western Mass, Fitchburg
2008 Obama/McCain: 70.3%/27.5%
Dem Avg: 62.2%
The liberal areas of western Mass, including Springfield and Fitchburg.
2008 Obama/McCain: 65.4%/32.8%
Dem Avg: 54.7%
Liberal areas west of Boston.
2008 Obama/McCain: 51.5%/46.8%
Dem Avg: 37.0%
Second Republican opportunity district. Conservative areas south of Boston.
Yellow, 5th: North Short and Northern Boston Suburbs
2008 Obama/McCain: 63.3%/35.0%
Dem Avg: 52.2%
Even John Tierney is safe here.
Teal, 6th: Lowell and Northern Exurbs
2008 Obama/McCain: 55.7%/42.7%
Dem Avg: 41.2%
Should Nikki Tsongas retire, a wave could give Republicans a shot here with the right candidate.
2008 Obama/McCain: 77.7%/20.6%
Dem Avg: 70.5%
Slate Blue, 8th: South Boston & Southern Suburbs
2008 Obama/McCain: 67.4%/31.2%
Dem Avg: 59.1%
Steve Lynch is safe here.
Cyan, 9th: South Shore
2008 Obama/McCain: 59.9%/38.5%
Dem Avg: 48.5%
Initially Bill Keating was thought to not be completely safe in 2010, but he easily won. Under a perfect storm, Republicans could have a chance here too.
And there you have it. Under the best of circumstances for the Republicans, it's 5-4 map, which is damn good for them. Under most circumstances it's 5-0-2. It would probably be 5-2 in 2010.