PT Cruiser

 The Chrysler PT Cruiser: Chocolate cake stacked and iced with buttercream, then covered in white and dark modeling chocolate. I painted it with icing color and luster dust to give a metallic look.

The sand was flour and brown sugar. This combination works better for two reasons - it doesn't clump like pure brown sugar, and the flour makes it the right color for sand on a Florida beach. :)
Sorry I didn't get better detail shots! I had another cake to do at the same time, and I didn't have the chance to get more pics.