Interesting. 5-8 kg ? That's a lot, and maybe not needed in my case. I'm invested in the samsung nx camera and lenses, I have 6 lenses already, so I'm kinda stuck with the system, I didn't bought the nx300 and nx500 for drone use, but now that I did, I think the nx500 could be good for that.
28 MP, 9 fps continuous shooting with stabilization, high res touch screen, 4k movie, possibility to take photos and movies with a "flatter" settings which maybe mimics a little a Red Camera flat mode.
Including a motorized zoom lens so I can change the zoom while the camera is up in the air.
As I said earlier, with the motorized lens the camera is only 500 gr, but other lenses are quite heavy, much more than the camera, so maybe with a setup like yours I can even use the heavy ones.
Too bad the "professional" drones sometimes don't have all the bells and whistles of the consumer ones like the superior modes of navigating (working well even when the gps is not visible) and obstacle avoiding of the Phantom 4.
What's the total price for your solution ? Drone, gimbal, video transmission (can you use a tablet or phone as a screen ? )