you should go to the page 2 in that catalog. they even stock the backpack for Parrot drone which is one of my favorites.
http://www.valuehobby.com/accessories/bags-cases.html?p=2
How about the backpacks provided by Valuehobby? they're all under $50, many choices for DJI phantom series quadcopters.
http://www.valuehobby.com/accessories/bags-cases.html