What if you designed a ski so that the edges were the exposed part of a metal layer that went all the way from one edge to the other, wrapping around the superior portion of the ptex base layer? That stiff support might even add rigidity/toughness to the base as well. The metal layer would of course be thinner as it crosses over to the other side of the ski, and thicker on the outside (exposed) edges. Otherwise i imagine it would be too heavy.
i dont know how well/thoroughly you could bind carbon fiber to a skis edges which is why i think a this steel layer might be the best way.