I found this video that shows a family that lives in an old converted street car. Over a decade, Claudine raise three boys in this tiny 400ish square foot house that was originally a 1920’s street car from Santa Cruz. Originally only having one bedroom, as the family grew, so did the house. They built a tree house and then a cob hut to allow their children to have a bit more space. It is interesting because the owner is working with the city to get her home legal. Lots of great commentary on this topic.