Hey Robert
I have learned that there are compromises. I found a product that can possibly out last the Matrice100's flying time but you are limited in payload. For your needs to carry a mirrorless or DSLR hands down you need either a Hexa or Octocopter.
I would stay away from a Quad to carry $$$ camera gear. You want redundancy in horsepower and stability.
In my case I am building an X4 Quadcopter to haul my FLIR but if and when I decide to haul my 5DIII the X4 is expandable enough to become a X4 with a second set of motors under the top motors.
Here is a video of an X4 that has been upgrades to an X8 quadcopter.
I went with a X frame quadcopter because I wanted larger props. The larger the props along with a slower KV motor will be able to carry heavier loads with a more efficient energy use = longer flight time. This is not an exact science but following these theory should provide me with an outstanding solution.