There are a few start-ups about 3D printing houses, but - at least for those that I have seen that actually demonstrated something - they seem to be the "usual" startup led by some brilliant people that never worked in traditional building/construction[1] and propose a new, revolutionary approach that resolve a non-problem (building the walls) and forgets to address all the rest of the building (where the actual problems are), let alone compliance with the various technical norms (very often local, i.e. not even country or state wide).
They can usually print a rudimentary shed in little time, but the same or better shed can be built in less time with prefabricated elements or in a little more time (at a comparable cost) with traditional means.
[1] and know nothing on the complexity of building a house