In our travels, my wife and I have come across some RV's that I think qualify for the unusual category. Here are a couple of them.
The first one was a home-built motorhome on an antique truck frame. The other one is a Towlite fifth wheel that raises and lowers like a Hi-Lo trailer.
Bob and Joyce
2013 CC Silverback 29RL
2010 Ford F250 XL Crew Cab 6.4 liter diesel
ATU Local 788