Buy your entire crew Osprey's Pixel Port backpack and make a back massaging chain, not for back massaging but for a massive circle where everyone can play Temple Run 2 and not feel so alone. The new backpack has a port and a see-through cover, so you never have to take it out.
The $120 bag (out this summer) is probably better with your friends anyway, because unless you're a paranoid tourist wearing your knapsack on your front or you've been possessed, it would be impossible to reach your tablet while it's on your back. Think of all the possible ways you could use this tablet tote. You could gather a group to play Kumbaya in unison on a syth app. You could edit a Google doc for a project while your entire group walks to class. Your entire family could stream an episode of Growing Pains while sitting around a camp fire. Sure the intent is so you don't have to take your tablet out while you're sitting on the bus or the train, but these uses are much more creative and better for promoting togetherness. And synergy.