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Mark, the guys bring up some good ideas. I agree with you that the subject photo lends itself to a landscape approach, but you could still play with some ideas to fit it into portrait orientation. The subject would have to be smaller, though.
Just a suggestion, but it's sometimes helpful to do some rough sketches to get the ideas flowing. It's quicker than having to digitally move things around. As you work through various scribbles, you often start to see something forming that works. At that point, move to the screen to try it out.
Personally, I think the layout you have here works well. You could add elements to take it to a higher level, but it depends on how much you want to tinker with it. Like, a texture (or four) to that gradient background, or multiple particle layers in the right places to develop the look of actually busting out of the state shape. (Here's a free download of some particle brushes: http://wegraphics.net/downloads/free-dust-particle-photoshop-brush-set/ )
Lots of other really easy stuff out there... just gotta look.