I didn’t start following this thread until you cross-referenced it from another one recently. I did wonder about the propensity of wide metal runners to stick to snow and ice. The glide is provided by the layer of water that the runner melts as it goes over the ice or the snow but this water can re-freeze on cold metal. Skinny blades (eg skates or metal edges), are not an issue but I figured that wide runners connected to a larger metal frame would be another matter. BTW, thanks for the tip that UHMWPE can be found at sign shops.

Also, have you considered the possibility of having runners curved at both ends? There will be occasions when pivoting the whole thing around you and letting it slide downhill in front of you will be quicker and easier than having to unhook the cords and either re-hook them at the back of the sled or hoisting it up to carry pack-style.

Stephane