I've never seen one either. The seriously-lacking-information website says they weigh 800 lbs. Thats reasonable if it includes everything in the photos (sink, bed, table, etc.). The camper has many windows, which makes it super nice. But if a person can't get in there and laydown with the roof down, not so good.
I first saw them on the net a couple years ago. But judging by the website, they may not really exist for sale. Sort of looks like some guys pipe dream. Maybe they are for sale, who knows. Send them an email.
I know I would like to have one because of all the windows, looks like it has some decent interior space with the roof up, and the low COG.