eHobbyAsia have the PPS XM26 MASS shotgun in stock:
Hot stuff at eHobby Now!
PPS XM26 Mass Shell Ejecting Gas Shotgun
Gas Pump Action Shotgun (With shell ejection system)
Diecast Aluminum Alloy Body Receiver
Aluminum 200mm Outer Barrel With Polymer 95mm Flash Hider (The muzzle brake can be pulled longer)
5 Position Polymer Stock With Rubber Pad & Metal Stock Pipe
Flip-up Front & Rear Sight
Aluminum Cocking handle can be folded up and down
Polymer Pistol Grip
Able to attach it onto a rifle after detaching the grip and stock and then attach it onto the rifle with an adapter
Able to hold 5 Shell Cartridge (12 gauge)
http://shop.ehobbyasia.com/pps-xm26-mass-shell-ejecting-gas-shotgun-pump-action.html