The Shield costing him the match somehow is pretty predictable and obvious. If it were me, this is how I'd do it:
Have Ryback destroy Punk and then prepare to set up the ladder and get the title. However, as he does, The Shield attacks him. He somehow destroys all three. But then Punk low blows him and handcuffs him to the ring post on the outside. Ryback struggles as Punk sets up the ladder in the ring and climbs up to grab the title, but then he suddenly breaks the handcuffs (should get a loud pop) and frees himself from the ring post (as Punk looks on the ring in absolute shock) but then as Ryback enters the ring to climb up the ladder to grab Punk (or just push the ladder over), The Shield (having recuperated during this time) tackles him in the ring and holds him down long enough for Punk to grab the title and run off with it as the winner. This would be cool because it shows Ryback surviving two different obstacles (Shield's first interference and being handcuffed by Punk to the post), only to just barely lose when Shield interfered for the second time right at the last moment.