The list is here for anyone who wants to read it (the reasoning and derivation was pretty interesting).

Now just take a moment for that to sink in. Each team has 2 starting corners, and most have a 3rd guy at nickel slot...but we'll disregard that for now. So the Bears field two CB's, Tillman and Jennings, who are ranked 2 and 5, respectively, out of 64 starting NFL cornerbacks.

That's insane. Neither of these guys have been "household names" across the NFL, and have between them a grand total of one Pro-Bowl invite--Tillman's last year. So how is it that two good, solid CB's suddenly jump into the upper echelon of cover guys? Simple: look at the other 9 players.

Start with the D-line: Peppers and Melton are consistently creating pressure (the latter is the top Pro-Bowl vote-getter among NFC DT's as of this piece's writing), Paea and Wootton are coming into their own, Idonije is as solid as ever, and McClellin's been playing his role very well. Pressuring the QB, manning their gaps, the D-line sets up the 7 guys behind them for success.

Speaking of the guys behind them, Briggs and Urlacher are as good as it gets at their respective positions, and Nick Roach, like Idonije in front of him, may not be the most spectacular player, but he knows his job and does it well. The Bears' front seven is excellent at gap control and run-stopping, meaning the defense does not have to drop an eighth man into the box on early downs, allowing them to effectively defend against the run and the pass. This in turn leaves cornerbacks "on an island" much less often, which leads me to the final point...

The safeties. Ah, the glorious safeties. A carousel, a revolving-door, a never-ending search since the days of Mike Brown and his back-to-back, OT-ending pick-sixes. Except, the search appears to be over. In Wright and Conte, the Bears have two up-and-coming young guys who hardly have their name called...which illustrates how good that back four really is.
Sure, Tillman and Jennings get most of the press and accolades (well-earned, I must add), but the play of Conte and Wright cannot be understated. Perhaps they've had their share of whiffed tackles, but the two are playing centerfield as well as anyone right now. In run support and pass coverage, the two are solidifying their places on this Bears' D, shaping their characters among these motley Monsters of the Midway, and that gives the two Bear corners a certain peace-of-mind, to jump passes and take them the distance, to go for the punch at risk of letting the runner slip away.

Yes, Tillman and Jennings are playing at an all-world level right now, and even perfect execution by the other 9 is not a guarantee for the CBs' success. They still have to finish the plays, catch the interceptions, reach out and swat the ball at the last second.
Yes, Tillman and Jennings will likely get the Pro-Bowl invites (which they will have to politely decline on account of a prior engagement--a date with destiny, as it were). One or both may even be selected as All-Pro's, and Tillman is currently in the running for DPOY. But let us not forget the two young'uns behind them, backing them up.

The safeties may not be making the plays, but they sure are making the plays happen.