Since you seem to plan using those pigtails you linked, the difference regarding the locations of the ports seems to be just the place where to mount the cable, right?
Ok, keeping the existing locations as-is would likely not be possible since the PCB will be in the way, but would it not be possible to have some holes, covered with removable blanking plates, on the front and back so that it would be easily possible to move the cable? I do not know though how to do that without ruining the looks of the box and how much cost this would add.
Anyway, if this has to be a decision that has to be made now, I will agree with danielbriggs:
I don't have Twitter so can't vote.
My vote is:
If it's USB Host / mass storage [USB on front, Ethernet on rear]
If it's USB Device to plug into a PC [Both USB and Ethernet on rear]