Many times trailers have been discussed on the form. So far there has not been any commercial trailers specifically designed for the RV12 turn Key. You will have to buy a trailer that will fit your needs and complete the interior design yourself. The best trailer design to show up on the form since the form started in 2008 was discussed on this thread posted 5/2014 by David K. Here is the link to the thread:
Though not an enclosed trailer it is built specifically for the RV-12. I don't know if the vendor (Rhino Aircraft?) could adapt it to be enclosed, like a mobile workshop for the plane?
Hemlockfield definitely has all the problems solved. Its by far the best RV12 trailer design I have seen. I wonder how many of these he could sell if he decided to build these......mmmmm....sounds like a new start up company to me.