Check out the Solar Park Model cabin created by the partnership of two
companies.  Based in Tallahassee, FL  
Simpler Solar Systems offers a Variety
of products for Energy Efficient Applications.  They have partnered with
Park
Models Manufacturing, Inc. in Cairo, GA to create stand alone Solar Cabins.
Greenpod Custom Compact Modular Homes - GreenPodsTM are compact
custom modular homes built for energy efficiency, indoor air quality, and
sustainability.