ASUL builds affordable modular structures. The problem with standard prefab homes are the costs associated with factory, and transport requirements. ASUL is transforming that model by creating a locally adaptable site-built process that combines a kit-of-parts model with contemporary materials and labor management practices. Based on this model they created The Savannah by ASUL ($TBA). The structure is 16-feet by 20-feet with a 8×20 foot cantilevered deck. It combines office space with a play room for the kids. So if you have the space you may want consider a backyard office.