I saw Will Smith's custom designed "dressing room" that he uses on film sets on some entertainment show.
The "dressing room" could be considered a motorhome because it is moved by a truck. The "dressing room" was driven out to the film set and then the truck part went away.
Smith's trailer is two stories high. He activates something and the trailer top rises and the thing becomes two stories high.
Smith has a recording studio built into his trailer.
The link below was given by a website discussing Smith's trailer but I don't seem to have a fast enough internet connection to see it properly.
http://www.andersonmobileestates.com/LowBa...ages/index1.htm