I have just finished reading the previous threads in here on Camera Bags. I have a collection of them. LAst 2 years I have used a Lowepro 300 AW slingshot - my shoulders and a neck just die after a while and I am looking for a backpack style case to take as carry on with all major domestic and international airlines. My head is sore from reading reviews and thinktanks, lowepro,kata etcs websites.
What I do need is room for a Canon 100-400, 3 other lens, flash, filters batteries, charger. What I liked about the slingshot was the quick action to get to my gear. Alas my back won't last. Ideally a tripod with be able to attach (not for airline travel) when bush walking. Even better would be provision for some personal items - room for sunglasses, hydration pack, a snack.
Thinktanks rotation 360 looked like a cool design but not enough room and the pack itself is too heavy for its size.
The Lowepro ProTrekker range looks good - any users here?
I dont need a space for a laptop. Well at this stage anyway.
What have other ausphotographers used on longer bushwalks and overseas trips???

Ideally it should not look like a camera bag.