I've seen those before. Pretty interesting concept. But I always thought they would be more useful as a fleet of emergency shelters or something. The only downside is that you don't exactly get a lot of space. You get a bed and maybe room for your luggage.
But if you had a large family or friends that wouldn't fit in a conventional RV, something like this might be a good alternative.
I wonder how it handles. It looks like it might be a bit back heavy.