Try Luzo Fuel in New Bedford. I just bought two pallets of deck tiles from them. Would have bought all they had but they said they had to save some for the local boats. Give them a shout they might be willing to part with some it won't take to many to do your deck.
The only company that made them stopped making them, couldn't find a buyer for the equipment and scrapped it. luzo bought the last of the stock on hand. As it stands now no one makes them in the 12" X 24" size. There is a product made in larger sizes for bridges but I don't know if it is exactly the same.