Recently I bought the Multistar backpack from Hobbyking and I am really satisfied with it.
I was searching for some time for a multicopter backpack. First I tried to check all available items, designed for multirotors.
Some were not suitable at all, and some were too expensive.
Later on I realized that the manufacturer of similar products make these for photographers, so I started to check those on the net.
However, those that were big size enough were expensive so me best bet was the HK’s product.