What are the alternatives to building houses with block walls in Nigeria?

Of course there is mud! Call is burnt clay, burnt bricks, compressed earth, they all serve to provide the walls in a tropical environment like Nigeria. But is it not time we looked at alternative methods that could slash our building costs, or better still bring some innovation that can add some touch of class to the art and science of building homes? How about building with steel, Sheetrock, aluminium etc?