Of course with an order that big, it would make sense for Boeing to also develop a stretched, higher gross weight, longer ranged version that could be used to replace the C-5A's.
I still think if the European military orders 180 C-17’s instead of the failing A400M program, it wouldn’t be just the current model with the Pratt & Whitney F117-PW-100 (PW2040) engines and the Boeing “flying boom” refueling receptacle. That level of production—especially given European local parts requirements—will involve installing Rolls-Royce RB211-535E4 engines rated at 40,100 lb. thrust and using a drogue-and-probe refueling system.