It sits at 26 feet with 15 feet of cargo space, our 08 crew is in it right now with a clear two feet more space if we had a bike in there, Santek built this as a simple trailer then did a bathroom/kitchen conversion, its a great support trailer for what we use it for. A guy down the street has a 24 foot Wells Cargo box trailer with Geni, AC and race support stuff for sale in his yard, I would get a 16 foot minimum box.
When I was looking for our trailer on craigslist in the IE, there were lots of options.
Dico, Santek, Wells Cargo, Carson, etc.