Yes, you are correct that a 140mm/dual 140mm fan combo would be partially blocked when mounted on the top. My dual 120mm setup is pretty much the length of the opening.

Hey guys, I have one of these cases and just recently finished my new build in it. If you guys have questions I can definitely try to answer them the best I can :) Pictures here: http://imgur.com/a/QRiQp Intel Core i7-5960X Corsair H105 with Noctua NF-F12 PWM (x2) ASRock X99e-ITX G.Skill Ripjaws 16G...