German company Technus make a curious type of manufactured house: a "watercamper" or houseboat. This is a byproduct of a modular system of modular floats developed for jetties. The houseboat is a large platform made out of two rows of floats to form a catamaran, with a caravan attached to the deck. As the floats are modular, this provides separate buoyancy chambers to improve safety. There are tapered floats to form the bow and stern.
Their English language web site does not seem to be working, but you can read a translation from the German.