Speck has a wonderful iPad mini case (http://www.speckproducts.com/tablet-ipad-cases/ipad-mini/smartshell-for-ipad-mini.html) which has a metal stripe on its right edge. I designed an almost invisible magnetic mount to this case. The mount requires 3 pcs of neodym magnets with 30x10x8 mm dimension. These magnets are very strong - they hold the iPad mini firmly on place. The mount is 95 mm long so you can use plugs on both sides to fix|hide the magnets if you wish. Print with 0.1 mm layer height, 20% infill. No support needed.