There truly isn't. I have converted Conexes into tool cribs,Generator houses, bunk houses and bathrooms many times over the years. Built a 40'x80' shop for a guy, using them along two sides. Turned out pretty well.
Like Wise, I have one I use for my Steam Engine, one for my Back up Generator and Three were sunk under the house for a cellar when I built the home! Truly impressive what a creative mind can come up with using these to build with!