Leesure Lite makes them. Light weight camping trailers for motorcycles or small vehicles. They have one that slips in the back of a truck.
Mine is the larger one , the Excel and has a gross weight of 255 pounds unless I stuff about 400 more in it which it will take. I like it , nice and light , easy to set up and does not cost me a thing in gas to tow it behind the Jeep. Same mileage with it or without it back there.
http://www.leesurelite.com/
Chuck.