I'm throwing this here:
FOOTBALL OUTSIDERS: Innovative Statistics, Intelligent Analysis | Stat of the Day: Quarterbacks Getting Hit
Basically, it says there were quarterbacks in the NFL who were hit more frequently than Campbell (no word on harder), specifically, Garrard, Schaub, and Warner, with Campbell getting hit roughly as often as Tom Brady or Matt Hasselbeck.
Aaron Rodgers was hit significantly less often, which might surprise some of you, but is quite in line with what my eyes told me, re: Packer games.