Not sure if this is exactly what you are looking for, but FFToday shows each DEF and a factor which rates the effect that playing a team has on the projected points.
http://fftoday.com/stats/fantasystats.php?o=3&PosID=99&Side=Allowed&LeagueID=87022I explained it poorly, but basically, here is an easy example:
Arizona DEF:
Week 6 (NYG): -61.2%
Week 7 (Carolina): +116.4%
So basically, you will expect Arizona to get 60% less than average against the Giants (good offense), and Arizona to get basically double the points against Carolina.
They also have these ratings for all positions/teams, so you can see where your good fantasy matchups are.
Hope this helps.