I found this Lowepro brilliant for my P4P v2. With four batteries, a camera and Epson BT glasses and a water bottle it weighs 8Kg. Light as a feather empty.
It is very strong comfortable to carry and even has its own raincoat packed neatly on the underside. Never failed me, top notch. Not cheap although I cant remember how much but would highly recommend it. The green thing is a raincoat for me so we both keep dry Notice the very good padding to make it a breeze to carry.