Now that we have a locale more suited to it, a Batman mod would be cool. Either based on the comics or the film, though I would like to see the Tumbler and Bat-pod. The abandoned mansion in Alderny could be turned into a Wayne Manor safehouse, there's a number of Algonquin skyscrapers that could be the Penthouse. The mobile phone could also be used well here, like if you destroy your vehicle, you can phone a number and it spawns a new one that gets driven there on it's own (as if remote controlled).
The phone has a lot of potential actually. Imagine having a "major backup" number which brings SWAT teams and Hunter Chopper Squads to your aid.