Years ago L Cee posted something, I think on the FRN, about plastic masts developed by the military that could be rolled up, and then unrolled in the field to be used as antenna masts. They seemed to operate on the same principal as a tape measure: they could rolled up into a compact wheel, like a tape measure, and when extended, their cross-sectional U shape gave them the structural support to allow them to be cantilevered, again, like the blade of a tape measure.
I don't recall the details, but it seemed like a neat idea. Perhaps if L Cee is still around he could comment, or maybe someone else knows of such things and could reply here.