Two GOP challengers that I know of are hitting hard on this as a campaign issue. They are Adam Kinzinger (IL-11) and Mike Fitzpatrick (PA-08). I hope there are more than just those two.
Fitzpatrick actually showed up with a bunch of his supporters at a “one-on-one” meeting the Democrat incumbent, Patrick Murphy was having. It got nasty. Here’s the youtube of it:
http://www.youtube.com/watch?v=pBUncXmE4Ec