i see hundreds of topics about people building or converting van, trucks and boats and bikes and such like to make camper vans but never see anyone building on a trailer to make a caravan from fresh why is that?
Good question but not having any official documentation to be able to insure it such as make or model etc. would cause many legal issues to say the least so it's not worth the hassle in the long term. The cost involved would probably work out more as well the same as if you bought all spares for a car and built it from scratch.
------------- Yesterday is already a dream and tomorrow is only a vision, but today well lived makes every yesterday a dream of happiness and every tomorrow a vision of hope.