There seems to be something about both DFW and ORD and long-haul service. QF bought 744ERs expressly to serve AKL-DFW non-stop, had the press release announcing the route, and then decided not to (using them SYD-LAX instead). Also announced SYD-LAX-ORD service 3 times a week, then a week before launch, after selling tickets on the flights, canned it (preferring to leave the 744s on the ground all day at LAX instead). This happened twice. The economics of these midwest to SE Asia/Australia flights must be quite intricate.
The 772LR does seem like a great plane, but I've heard that CX is much more interested in the 773ER which suggests it is more a 346 replacement and frequency boost for existing routes than opening up new ones. Plus the 744Adv seems to be a sure thing now with at least 5 airlines serious about it. The A380 delays are really ticking SQ off and it seems ready to sign up for the 744Adv now, if rumours are to be believed.