Think Tank Helipak, it's the one. I've bought a lot of backpacks over the years and they have the best design for drones IMO. You have so much room you have to be careful about weight. You can store batteries under each motor arm to make room for the DSLR if needed.
The best price I've found is $150 at B&H Camera.
The best price I've found is $150 at B&H Camera.