Luke,
there is no one fits all solution, neither for camera, nor for lens, certainly not for rigs either !
Its all in the cinematographical idea at the end. If you choose to shoulder a camera you get a totally different
look and feel then with a Easy-Rig, or steady cam. The same is for sheer body height of the camera operator.
In certain configurations you can lower your camera below shoulder hight, using different rods and connectors,
while using shoulder pads and battery pack as counter weight on the back.
I am pretty sure with a bit of tinkering you can find the right components and keep a cam under the arm and build a 'cage'
around your shoulder with pad on it. The configuration of my rigs change faster then the lenses on most days.
If you need to walk a lot - run and gun, the only thing that really works for longer settings is a Steady-Cam, Exoskeleton, Easy-Rig.
But then again it changes the flow of the image. In the worst case, use a steady-cam and add motion effects in post to a certain degree.
In addition, if a camera does not have a certain mass, its useless in most cases. You simply can't handle a Pocket Camera the same way as a full size cinema camera - but your back (or mine) pays the price :-(.