So I think we should clarify this a bit.
I think there is a difference between cockpit floor tiles, and deck padding.
I've seen some sport keelboats that seem to have textured foam glued to the deck, I assume to limit bumps and bruises for crew, say, slipping on the foredeck during a chute douse.
Then, there are grates that some people install in the floor of the cockpit, mainly to keep one's feet drier when there's water being sloshed in, either from a cockpit drain, or water coming in over the sides... I've seen beautiful custom teak lattice grids people have had made.
When I think of interlocking floor stuff, I think of either foam pieces that make playroom floors for kids, or a turquoise plastic gridwork product we used to put on the floor of the ski shop around the ski tuning machine, because that thing spit water all over.
Brian
I use DRI DECK panels available through WEST MARINE in the flooring link.
They are extremely durable a little tough to put together, pick a warm day.
You could cut them to shape with a pair of sheet metal cutters.
They keep all the dirt and sand out of the cabin and never look dirty.