Don,
I also have the LowePro Nature Trekker II AW. I am very pleased with it's quality, construction, fit, etc. I've taken it on numerous trips and it's held up like a champ.
Just to give you an idea on size, right know I have in it: 1 body, 70-200 2.8 L IS, 25-105 f4 L, 10-22 wide, 15 fisheye, lens baby, 430 flash, batteries, cables, filters, cleaners, hoods, extension tube,misc. ...and it is slam full. I have the small day pack that can be attached to the front of the pack that I use for layers (jackets etc.), the water bottle attachment, and the tripod attachement (Gitzo 3530lsv + Arca Z1). As you can see it can handle a lot. My only concern with this particular model is if you will be able to fit all your lenses. The 100-400 is big/long and would have to battle with the 70-200mm for the center position, etc.
The other thing to consider... do you realize how heavy your bag would be with all the stuff you listed? With all the gear I have, which isn't a whole lot,my pack is over 40lbs. Now, I'm 6'-3", 240lbs and pretty big and fit, and luggingmy pack around is VERY burndensome for long periods of time. Especially traversing hard terrain or up and down Mts... ...my Yellowstone trip nightmares are starting to come back now.... thanks for that... So please consider what you are going to use you backpack for; trip length, type, temp., terrain etc in your decision. You can then prioritize you gear and save yourself from a very painful situation.... [:'(]
In conclusion the nature trekker II AW model might not be the right size for you, but Lowepro makes great products and I would recommend anything from them.
- Jason