I've never been a professional photographer, but I was a professional journalist (writer) for a long time and did a lot of published photography then. I've more or less solved this problem by using three systems -- Nikon, m4/3 and a Sony RX100 pocket camera. I don't need more quality for anything I do than I get from a D3/D800 combination, but I do need a large case. With m4/3, I can put the equivalent of the Nikon system (with three Panasonic bodies) in what amounts to a briefcase, and the quality is easily good enough for all newspaper and most magazine work (the quality is different than, but generally better than film.) The RX100 is easily good enough for all newspaper work, as long as you have the light.
Another part of your solution might simply be to take some risks, and winnow out your gear. I went to Iraq a few years ago and carried a D3/D300, the three Nikon f2.8 zooms and three or four primes. Eventually I pulled most of the guts out of a small Kata backpack which would hold the two zooms I didn't have mounted on the D3, plus some other stuff that I needed. I left everything else at the base, and carried the D3 in my hand with one mounted lens. If the D3 had failed, or if I'd needed a specialty lens for something, I would have been out of luck, but I took the risk and never had a real problem. If I were to do that again, I'd take the m4/3 system, which would allow me to carry two bodies and a half dozen lenses, including some good sharp zooms, that would do more than the three Nikons did, in far less weight. (Panasonic offers an excellent and compact 100-300 which gives you a 600mm equivalent.) But then, the target for those photos would be video screens and newspapers, and I wouldn't need the resolution that you might. I also did some early morning flight-line shots with the D3 that I'm not sure I could duplicate with the Panasonics.