Magnets are the way to go man. I'm using a magnet with my soon-to-be shield and so far it works great. Just make sure you pick a magnet that isn't to strong or to weak. I use the magnet to 'backpack' the shield and as the upper forearm 'strap' mainly for speed and ease of use (plus I can do the kick-and-catch move from the elevator scene in the trailer:cool).