I still don't understand exactly how the shield would stay there. Does it just magically hang there until you reach back for it? Does it clip on? If it clips on, is it a fast release clip? If it's fast release, who made it? Can they even do that in the TES world? What materials would they use? What would it clip to? A backpack? What if you aren't wearing a backpack? Would it clip to your steel armor? What if the character is wearing a tavern outfit? What if you're wearing Steel Plate, don't you think that armor would interfere with the kind of arm flexibility you would need to reach up, over your shoulder, to grab the handle of the shield? Would that handle just kind of magically shift so you could grab it easily, or are we back to some kind of weird, out of place fast release mechanism? Just how quickly do you think you could ready that shield when a bandit is rushing at you swinging a war hammer?
Just because Dragon Age did it doesn't mean Skyrim needs to do it. It didn't make sense in Dragon Age, and it wouldn't make sense in Skyrim.
/ragerant
On the other hand, showing that second sheathed weapon is something I'd like. And it makes a whole lot more sense than a shield on your back.
http://www.herr-der-ringe-film.de/v3/media/specials/teaser/teaser29-cb57644.jpg

I'm pretty sure templars used to have their shields on their backs, but I dont know what they used to hang it.
They use a belt that goes through the handle
