Blue Dog democrats are like Bigfoot. Every couple of years around an election, a couple of grainy, out of focus photos of them show up campaigning about fiscal discipline but after the election we find out it was just a lib in a conservative suit. There is no such species really.
I think voters have sent a message too. Voters in these more conservative districts, even if they like their Blue Dog Democrat congressman, realize that a vote for him/her is a vote for Nancy Pelosi as Speaker, and a vote for the whole slew of liberal/radical Democrat policies in Congress. So voters are wising up and abandoning their Blue Dog Democrats.
John Barrow D-GA is as close to a Blue Dog democrat as you will see in the South. The Republicans try each legislative session to re-district him out of the House and the Democrat establishment runs a more liberal candidate against him in the primary. All Barrow does is win, showing the power of incumbency.
We can say the same about Romney.