I purchased this one for my PA3x (on sale at $100). It's about the hardest soft shell I could find. The weight is about 22 lbs. Plenty of solid padding for protection.

SKB SKB-KB76 76-Key Keyboard Bag with Wheels

IMPORTANT: That PA3x is HEAVY. I bought a case before this that the handle started to rip. I wouldn't use the above case without "supporting straps" that wrap underneath it. I was looking at "Strap-a-Handle"