I was lurking about this site a couple of years ago while looking for a travel trailer to convert into a "Toybox". My show car is 18-feet long and 6' 5 1/2" long. It also weighs in at a beastly 5,300 pounds.
I had some unusual ideas about opening up the back of an Airstream but it was very complicated. Craig Dorsey suggested that I look at the Spartanette trailers because the "canned ham" shape lent iself to being opened up like clamshell.
Craig had a Spartanette Tandem he was willing to convert for me but I would have had very little lounge space on that model. I found that the Royal Spartanette was 7 feet longer giving me a living space of 11 feet and garage space of 21 feet.
I found a virtually dent free '51 Royal Spartanette that had spent it entire life outdoors which left it with a nice thick patina. When I gutted it I found out all about dissimilar metals as the vast majority of the steel screws that attached the aluminum ribbing to the wood studs has literally disappeared. I installed 2,000 new fasteners to stabilize the body before lifting it off the old chassis.
If you're interested I've documented the project at:
P.S. I'm looking for a master riveter in the Detroit area.
Farmington Hills, MI