You're probably right, but there's no reason to think the Chicago inner city Dems are willing to give up their safe seats now when they emphatically would not in 2001. So, the collar counties basically involve five GOP districts (IL-06, IL-08, IL-10, IL-11, IL-13 - that's Roskam, Bean, Kirk, Weller, and Biggert). As I noted, the first priority would be to make IL-08 a true Dem seat, and after that they need to pull another seat out of what's left of IL-10, IL-06, and IL-13. I assumed that IL-11 would be out of play because it would also be involved in crafting another Dem seat out of (primarily) IL-15 and IL-19.
I think you'd end up with Kirk and Roskam combined and with Shimkus and Johnson combined. The new eastern Illinois IL-15 seat would probably be a Toss Up, and it'd be something of a mirror image to IL-17 in western Illinois, picking up Dem precincts all the way from Joliet in IL-11 in the north to Paducah in IL-19 in the south. Then you'd have a new Dem district essentially like an arc along the western suburbs of Chicago. IL-08 would pick up the waterfront from IL-10 and Wheaton from IL-06. I suspect that would all work out. The odd men out would probably be Roskam and Tim Johnson.