Based upon my experience in Malawi, and Trinidad & Tobago, the big opportunity for homebuilding is in the developing countries of the world. These countries need inexpensive materials, and quick and simple methods of construction. They have large unskilled and semi-skilled labor forces.
The housing needs vary by location, with simple basic shelter for a start. Many locations will not have running water or electricity.
There are modifications that can be made in the construction of a home, that can adjust to these variables, and not compromise the stability of the home. Based upon my experiences and knowledge, these problems are easily solvable.
The economic benefit resulting from the exportation of the Intellectual Property, and the materials necessary to mass-produce homes throughout the world would be considerable.
Here are some pictures the from trip with Habitat for Humanity's Global Village Program in Malawi, Africa:
Building Basic Shelter in Malawi, Africa
Examples of International Interest