The one thing I have learned over the years - after owning many bags - is a bag large enough to carry everything is too heavy to carry (or at least to carry comfortably).
You really don't need everything in one bag. I use a "day bag" concept, wherein I only take what I need for the day. And yes, that means I have two bags (the other one stays in my hotel room, trunk of the car, or wherever I am). The second bag contains chargers, cables, and stuff I don't immediately need.
Regardless of what your concept is, take a look at Think Tank bags. They are among the best ever made, and have a lifetime warranty, which only a couple of brands have. They are often the choice of professional photographers.
Having such a bag won't make you a professional, but pro's tend to be hard on their equipment, so you know the bags are very durable, and will stand up to years of use.
Think Tank has shoulder bags, backpacks, convertibles (which I relly like), and suit-case style, and many sizes of each. You should be able to find one to fit your equipment.
My current bag of choice is a Think Tank Speed Freak convertible. Convertible comes from the ability to use the bag as a shoulder bag, a waist bag (with a hide-away belt), or a combination of belt and shoulder strap, which helps the comfort level a lot.
Unfortunately, the convertible series might be too small for you though. The largest bag of the series, the Speed Racer, can hold a pro-sized DSLR (with battery grip), plus 3 lenses - one of which can be a bazooka sized 70-200mm f/2.8. You could possibly get two camera bodies in the bag without lens attached, but it is debatable.
However, since the speed bags have an attached belt, you can buy modules that will hold lenses, and other accessories that will attach to the belt.
One thing you might like to try is to visit a camera store. Most of them will allow you to bring your equipment to the store, and test-fit it to their bags to make sure you get the right size for you.