This line of custom-painted ovens is based on our regular mobile oven + decoration on the exterior. The decorated and non-decorated ovens are supposed to perform the same. Performance is very decent and has been discussed in another post on this forum:http://www.pizzamaking.com/forum/index.php?topic=22949.0
There is 1" of ceramic blanket inside that double metal dome. The exterior does get very hot overtime. However in my experience any mobile pizza oven has to sacrifice heat retention abilities - heat retention needs mass, no way around it. Even if you add 3" of insulating blanket the heat still has to be stored in something and unless your oven is made from clay, cement, or bricks you are storing heat in a thin sheet of metal... A metal pizza oven means speed but lower heat retention, if you want pizza-baking temperatures to last for hours you need to maintain the fire. But if you need to cook 20-30 pizzas in 2 hours it's a perfect oven.
Stonecutter, if you like Van Gogh please see below a picture of current work in progress!