Indiana 7th could also be another one. The district swung heavily to Obama, but Carson does have a decent challenger, and his mother didn't rack up huge margins in the district when she ran.
http://www.drmarvinscottforcongress.com/
Marvin Scott isn't that great of a candidate, though it will help him that's he black. He got slaughtered by Bayh in 2004, only garnering a little under 40% of the vote. He may hold Carson below 60%, but barring any major gaffes, this should easily stay in the Democratic column.
