IMO, this is the defense I'd go with playing the Steelers.
The Steelers have had incredible success recently running up the middle, and that is where our biggest weakness on defense lies, which of course has always been pretty much the strength of our D. Terrence Cody and Kemo are going to get killed if the Steelers play the run like they've been doing recently, and it's all up the middle. I'm actually confident about our run defense from the edges with Suggs, Upshaw, and McClellan, but we seriously need to address the middle which could get hugely exploited.
I say we play Ngata at NT and bench Kemo/Cody, while playing a rotation between McPhee (if healthy), Tyson, and A Jones at RE and LE. Put Upshaw and Suggs in their natural positions, Upshaw can rotate with McClellan (who is a very good edge setter), and bring Kruger in for 3rd downs as a pure pass rusher nothing else. Infact, I'd go with a 4 man line of Suggs, Upshaw, Kruger, and Ngata on 3rd downs, which is going to bring some pressure. Line Suggs and Ngata on the left end of the defense on 3rd downs to exploit the weakness of that Steelers line on the right side, going up against the rookie Mike Adams.
Personally I still want to see McClellan start in one of the ILB positions, but the coaching staff is obviously not going to do that at this point, so just put McClain and Ellerbe there and hope McClain can have a decent game. We all know what the secondary is going to be (providing Jimmy Smith is healthy), but I'd replace Grahame with Chykie Brown for the nickel corner position.
So basically this is the front 7 I'd go with...
On 3rd downs....
Ellerbe/McClellan (blitzing strong side/contain)-Bernard Pollard-Chykie Brown (Nikel)
Take McClain out as he is terrible in coverage, and bring in Pollard covering Heath Miller while bringing Brown in as the nickel corner. Cory Grahame can come in as the extra safety. Ellerbe is very effective as a blitzer, so that's what I'd have him do on 3rd downs for 5 man blitzes, and bring in McClellan to help contain Roethlisberger in the pocket.
This is just a fans view, I'm sure, and I hope the coaching staff know something better to put out in order to beat the Steelers. It's going to be a huge game, but for now, I will be rooting for the Chiefs big time tonight.