Red Lion -
I am trying to figure out how the "skeleton" would be stored. I imagine something like an umbrella or one of those unfolding outdoor canopy tents :
However, in your case the geometry is much more complex. A bumper *is* similar in shape to a canoe, so maybe blueflame is implying your tent structure.
For a 1.0 version, I wouldn't think in terms of an inner skeleton. I would combine Bicycle Bob's and blueflame's suggestion. I would get spandex and see how it stretches over the shape of your bumper. Kind of like a car bra, but without the emphasis on form-fitting.
This is not a stow-away option, but as someone else suggested, getting a used bumper and turning it into an aero shape is a great idea. That way you can keep your original bumper in storage while making as much of a mess as you want with your aero-bumper.
CarloSW2