I would really recommend getting a custom hard case made with light weight luan plywood over soft cases. Been there done that. The soft cases such as Gator weighs 25-26 lbs. The case I had custom built from nycase weighs 20 lbs with wheels.
Here's one for the PA3X. You'd just have to contact them and specify your dimensions.
http://www.ebay.com/itm/Lite-Duty-ATA-Case-Recess-Carpet-Lined-For-KORG-PA3X-PRO-ARRANGER-76Key-Keyboard-/401140704576?hash=item5d65d96540:m:mb8mpGi34WBVK_FhfI9GRdw
Here's a post after I had mine made after spending months trying something to fit my Tyros 4. It gives all the reasons this is a good idea IMHO.
http://www.synthzone.com/forum/ubbthread..._Als#Post330486No more soft cases for me. No more broken zippers, frayed fabric, etc, etc and less weight for a more secure case.
ScottL