As CNET points out, the Post Modern Skateboard—basically, a $100 pair of 10-inch, round wheels with foot platforms—seems to be more spiritually akin to a caster board, a two-wheeled, skateboard cousin consisting of two decks joined by a metal beam. But seeing the skater's two feet moving independently in this video reminds me a lot more of roller blading or figure skating than anything else.
The "board," however, does come with an extendable rod that can be used to connect the two skates. If you squint at this contraption with the rod in place, you can sort of see a shadow of its former self. [Hammacher Schlemmer via CNET]