This is close
, but much smaller
It's technically not CPS. It has a bladder, but it's purpose is to separate air and water. It's pre-pressurised and (as the air volume is greater than the water volume esp. in larger ones) the pressure drop-off less significant.
Dusty's is basically two of these tanks, strapped to a backpack frame, with a large pressure hose running to a hand grip with a ball valve.