So, Mornblade And I Are Discussing Iron Man 2 Last Night....
...and specifically, the stinger after the end credits, where Thor's hammer is being excavated. I mentioned to him I was wondering what they would do with it. They can't transport it out of there. Thor's hammer has a magic spell on it, that only someone pure of motive can lift it. Longshot could lift the hammer, for example. But a bunch of spooks, shadowy government agents from SHIELD, would not be able to lift it.
While thinking about this, it occurred to me that Rhapsody from Sound Waves could lift the hammer.
With that in mind, HERE IT IS! THE CROSSOVER YOU'VE BEEN WAITING FOR!