Let’s say a tiny or small house fits in your world view, except you crave a larger footprint. More office, sleeping, hobby or hang-out room might be nice.
Here are a few companies offering kits or prefabs, which handle materials (both) and construction (prefabs) for you.
Prefabs: assembled on your land

This Greenbuild cabin, measuring 801 sq. ft., is the smallest prefab from Resolution 4 Architecture. (re4a.com)

With a streamlined and hip feel, the Greenbuild cabin offers plenty of square footage to add your touches. (re4a.com)
Kits: materials delivered to your land

This LVM modern home, shown with dark cladding, offers 693 sq. ft. Its kit may be ordered via the architect. (Rocio Romero)

In the LVM, there’s a main floor bedroom and great room. The place calls for mid-modern decor. (Rocio Romero)