That's pretty cool, I like the flamed one and can see how that would reduce the wake area of a full-size truck. The roof is slanted downward a little steep but I wonder what a tuft test would look like on it. I've seen quite a few camper-like trailers with the teardrop shape and I saw on TV where that style has been around since around the 1930s before roadside hotels were common.
I saw another link with a "streamlined" car hauler that was designed by a very reputable race car designer who built the original Cobra Daytona coupe. It can be seen at:
http://www.saac.com/files/orca.pdf
Note the PDF file format.
Remember this is intended to haul a race car and the general assumption seems to be that you would pull this with a pickup truck. There's only so much one can do to reduce the wake area and still be able to load a car and this design adheres pretty much to convention on the rear of the trailer. Also the design is somewhat limited IHMO by sticking with aluminum for the top and sides. Some fiberglass would allow better streamlining and more design flexibility. I really don't like the scallops down the sides and it looks like it turns the rear end of those scallops into air brakes. The only thing I can think that they are for is to stiffen the walls and prevent panel flexing but there are many more aerodynamic ways of doing that.
All in all it's a decent attempt but there's a distinct shortage of data to back up the design's validity. The only reason I think it's worth mentioning is the guy did one heck of a job putting a decent Kamm back on the Daytona Coupe back before people understood the importance of aerodynamics even in racing.