Long ago a guy in Hot Springs, Ar. wanted to build tent trailers and sell them, it began as a DIY project, very nice camper, all aluminum box, huge icebox, etc. Couldn't sell it for what it cost to build it.
Then he got his stuff together and started the business end, established his company, had decals for his camper made, Camper DeVille was born. The company was successful enough back then, more in the rental of campers, but he passed away and the company folded.
Starting a business as a legal entity is not a big deal, a Limited Liability Company is the most popular small business, for many reasons.
I came close to building some utility trailers, tilt bed, ramp, 4/5x6/8, then family was building Bear boat trailers (Bass Pro contract went bigger time), I passed as I was too busy getting irons out of the fire. That's just to say, a fabrication company isn't hard to start especially without employees and buying parts/materials wholesale and subbing out labor.
Where to start; check with your DMV to see what they want to register a commercially built trailer, most likely it will be Organizational documents on the company. Apply for a fabrication/dealer license. Then receipts for materials used to build the trailer, initial inspection, then boom, done! Simple.
Things for a utility trailer; tilt bed/body, winch plate up front to mount a small winch for utility work and loading, like a dead riding mower. Mounting brackets on the rear for camera, track systems inside body to lock loads down, D rings, lights, spare carrier, get up to 16' +, have some brakes.
Camper version, I'd suggest you go modular, removable fixtures, I might want to take a Triumph TR4A to a sports car rally one weekend, take the camper to the lakes the next weekend.
Main point, start a company, give it a name, people won't know the company, so what, they know it wasn't built in a garage on a weekend by a guy wearing bib-overalls......or was it?
