I was thinking about chequer plate... Slippery when wet? Noisy? And it still needs marine ply or similar to fix to, so although the steel might live forever, the marine ply won't, so maybe not such a good idea...
Not according to the 'experts'...
"We have purchased phenolic ply from China which looks very good but the ply veneers are invariably a softwood/hardwood combi, eucalyptus or poplar, and the construction quality isn’t the same standard as European plys. We now buy Russian or Latvian phenolic ply with a birch core, the quality has proved much better."
I haven't got a clue, but I believe everything I read on the internet (apart from Wikipedia, obviously!)