I don't have madden 07 yet(stupid lack of money) but in 06 i made a full 4-4 defensive playbook. It's not too bad against the pass if you have a good free safety. If the team im using has a bad free safety ill sub in the strong safety instead. ie. the ravens with ed reed.
The thing I ever did was (In the past that is) If you were the steelers, put Randle El at the RB and Bettis at FB, but idea ever! Just like the Deuce Bush thing. I think you could work it with Randle El and Portis!