I recently talked
with a fellow at a boat show who was selling the "Clear Bra" film protectant. He
had it in thicknesses up to 40 mils. It is sold as a clear film applied to
protect the fronts of cars against dings or he was using it on boat hulls and
trailers. The stuff was perfectly clear and might be what you're looking for.
Here is the website:
http://www.clearbra.net/
Let us know if this works as I may try it when I am lucky enough to need
it.
Kai