To move the topic a bit off subject: Given the structural and maintenance advantages of wing pylon mounted engines and their one principle disadvantage (longer landing gear) why don't we see more large high wing passenger aircraft?
From a fuel systems point of view, in the case of multiple pump failure, gravity feed uses up most of the fuel in the case of a low wing with dihedral and underslung engines, whereas a high wing with anhedral could leave a fair amount of unused fuel in the tips.
In addition, wingtip surge tanks are self draining on a wing with dihedral.