I think i remember where I saw it. Jesse at TLT(trail less travelled). I could be wrong.
The comment about over metal makes sense, strength wise. I can't see how it would be strong enough on it's own. I just like the idea of having less friction than metal.
My over all problem is skids bought from the mainland companies all charge shipping the same cost as the product. As in I pay double... I cannot find someone on my island who will let me use there metal brake, otherwise I'd try to make my own.