Right on the coast, it's very common. Especially on those overgrown sandbars they call islands. Usually the bottom story is a place to park the cars. Then the living quarters are on top, about 8-12' off the ground. Or, well, off the sandbar anyway.
Being a mountain boy, I find it fascinating that people actually build entire little towns, complete with gas stations, on those overgrown sandbars. Great place to visit, but I can't see buying property there. It's just a bunch of sand.
I don't feel right unless I'm surrounded by gentle, rolling green humps anyway. I don't know how you flatlanders stand it. Get down in flatland, either you can see too damn far, or there's no sense of how far anything is because you're surrounded by trees that are all on the same plane seemingly for eternity. No up, no down, no topography at all in flatland.