Molded carbon fiber fuselages would only be practical if some company offered a complete aircraft kit. First you need to make the male fuselage plug and then make thick fiberglass molds with external steel stiffeners to prevent the molds from distorting. However, construction for the builder would be greatly simplified as the entire fuselage could be made in two bilateral halves.
The big question is could enough kits be sold to offset the tooling expenses?
"For we are not gods and creators; and the controversialists have debated whether the All-Plastic Power itself can do more than mold" from chapter 75 of the novel Mardi written by Herman Melville. Published in 1849