the $300 house .. meeting real needs or a huge potential failure based on misconceptions?

The $300 House is a concept that came out of a blog post at the Harvard Business Review.  The idea is a mass produced, mostly robust, mass produced-for-profit dwelling for the third world.

Since then there has been quite  bit of criticism of the idea - a sampling of positive and negative comments.  I'm guessing you really need to get the culture right and solutions that involve the end users as much as possible are going to be more sustainable.