I have seriously considered building one in the past. Have it fully self contained, 4x8 front six feet as a bathroom with shower, sink, toilet, water heater in a cabinet etc.
Back 2 feet separated by a solid wall open the barn doors to a galley kitchen with sink and stove.
I cook and pit for...
Contractors put ladder racks and pipe racks on enclosed trailers all the time. Maybe check with your local truck accessory shop and see what they have.
Yes I am still using the original 5 lug truck axle. I have pulled it thousands of miles with no issues, I put about 600 on it 2 weeks ago. I am looking for a deal on a 6 lug trailer axle with brakes but that is mainly because want the lug pattern to match my at least a couple of my tow vehicles...
Along with the roof rack I setup a basic tarp awning. I used loops of para cord to attach to the rack. For poles I used electrical conduit, the heads on 3/8 bolts lightly press into 1/2 conduit.
For stabilizers I used trailer tongue Jack's that swing back I welded a piece of 2 inch square tube to the back of the mount bracket that slips into the receivers I put in the ends of the bumper.
I initially put this trailer together in 2009. It is the back half of a 2wd 1979 toyota pickup that parted out. It did a SOA on it and ran 31 in ch tires on it.
I used it as just a general use trailer for a few years, camping, moving, yardwork, etc.
Put a shell on it and my wife used it for hay...