Admittedly this idea is not my own (I heard it on the Francessa show), but its a good thought that I think is worth mentioning. Instead going with our base 3-4 package we should drop a backer and add a safety (Smith or Dig). Then we could lock up Jackson with Revis and bracket both Gates and Floyd. This allows us to zone blitz Rivers and match up a safety with one of the backs rather than a LB. Their backs against a safety favors them, but it keeps completions short and takes them out of their vertical passing game. Forcing them to dink and dunk, while swarming the ball carrier and making hard tackles is the kind of game we want to play. It'll take away their ability to strike quickly and make them grind out drives.
This package allows us to show a lot of freaky looks to Rivers, which could create some confusion, as Rex plays the mix and match game. It also provides for bringing pressure quickly, which our forte, with speedy D-backs rather than backers. This package would be a perfect way to get Smith involved since he seems more adept at playing down hill rather than dropping back into coverage. And its also a way for us to prevent our LBs with tweaked ankles from getting exposed in open space.
If we can turn this game into a physical battle where each team must make long, grinding drives we have a very good chance at winning.