I will second McHale packs. That is what I have had for a number of years now. Dan can work with you to customize a pack for your needs and it will cost less than either of your bodies.
If you are wedded to full-frame bodies, have you considered the Sony a7 or, for especially for landscape purposes, the a7r? That would save significant weight and size, and the quality would not be compromised. With an adapter, you can still use your Nikon lenses.
I don't understand the reason to carry two bodies if one of them is stuffed in your pack and not ready for quick action (unless you are concerned that one will fail on a trip, but to me that is pretty heavy insurance).
You have some excellent equipment, but not a kit that I would want to carry for long unless I had a beast of burden. Personally, on a backpacking trip, I carry my APS-C SLT with a CZ16-80mm lens and polarizer filter. I have also carried a tripod and recently bought a version that uses my hiking poles for two of the legs. Not as flexible, but considerably lighter. To me, a tripod becomes more important than many lenses.
Last week we flew to Seattle for the week and I did bring my 70-400mm, but I find it quite difficult to get the sharpness that I want at 180mm and higher without a tripod. It is a heavy lens, just around the weight of a 70-200mm f2.8 (which I have shot with before in a studio setting). I did not consider taking it for my climb though.
By the way, nice shot. Where was it taken?
I would also consider taking smaller aperture glass since lighting is not generally an issue in the backcountry and, when it is, the tripod alleviates the issue. In any case, HYOH.