The above video got me excited about the potential for building modularity into a community design. Almost anythiing that I can think of has components that can be determined in advance, and designed in such a way so that they can be replaced, rather than throwing the entire item away. This would includes the phones depicted above, laptops, homes and cars. The video below talks about a car design that has been developed with modularity in mind.
It shouldn't take much thought to see how modularity could be built into home design. Rather than trying to build a home all at once, or being content with a trailer or R.V. that packs everything into a small space, why not consider building a kitchen that would serve as a standalone room in a house, then build the office, bedroom, bathroom and so on, as time and materials allow? The major difference is that all of the walls would have to be constructed as exterior walls initially, but in such a way that they could be butted together against the other walls without gaps and without too much width being used up.
I worked in the cabinetmaking profession for four plus years and build a lot of cabinets using this method. Pieces of melamine were cut for the sides, bottom and back with cross strips for the fronts on the base. Oak or maple doors closed off the fronts. Then, when the time came for assembly, we simply screwed the cabinets together, side to side, as per the design. We didn't design the entire kitchen to be installed fully assembled (as a house is when it is finished). Rather we designed it in such a way so that the cabinets and their components could be carried in easily, then put together on site.