In Germany they are called "bauwagen" or builders wagons and are used as trailers on construction sites. A bauwagen "trailer park" is called a wagenplatz. I like the shape of the roof on these. Below are some examples of this type of wagon.
How to Build a Gypsy Wagon: Step by Step Instructions--a great Instructable and a beautiful Vardo trailer. Inspires one to quit the day job, get busy with a saw, hammer, etc. and take to the open road.