I understand the reasoning, but I'm not sure I agree with the decision.
Champ Bailey is the ultimate shut down guy, but he is human. If he makes a mistake, he will likely be all alone on Harrison.
I'd go with Harrison, if for no other reason than he is the only one of the three (Harrison, Chambers and Plaxico) that has Peyton Manning throwing to him. Plaxico could go off this week, but then again, Eli could tank and leave him out in the cold.
I'd be very worried, but my opponent's running backs are Steven Jackson (hurt), Deuce McCallister (really hurt) and Ladell Betts (bye week). Which means I'm going against the Bears' Adrian Peterson and Michael Pittman.
Marvin vs. Champ honestly couldn't have come at a better time for me.
I think you are over analyzing a bit. Match ups are important but with top players, it's tough to sit them over lesser talent no matter how the latter has produced in the short term. I would go with your best players and hope they produce because if you are wrong, then you could miss out on a huge game.