In our area (near to Mitiempo) it's available in 1/4" and 1/2" sheets... the quarter is around $250/sheet and the 1/2 is $300 (4'x8') Considering that you'd likely have to laminate the 1/4" stuff to marine ply anyway, the 1/2" is the better way to go if that's strong enough on its own.
Builders such as Beneteau are using synthetics nowadays.. to my eye it doesn't quite have the "look".. they've gotten away from the contrasting white strips.
Nothing quite dresses up an old boat like a new sole... It would be interesting to compare the stuff SD refers to.... I've not seen it around.
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)