People are already building house components on an assembly line in a factory. By components, I mean entire rooms and sections of houses.
I wish some brave soul would undertake the task of creating, I don't know, the VW bug of trailer homes. Doesn't have to be a luxury thing, just something with character and identity. Something you can be proud of because it has a personality, just like the millions of others like it.
If "the VW Bug of" means a willingness of the manufacturer to modify the traditional chassis and body layout to better accomplish design goals, then GMC did build something along the lines of what you describe. ("something with character and identity. Something you can be proud of because it has a personality, just like the millions of others like it.")