There is a program called REED: Renewable Energy And Ecological Design in the Green Mountain College in Vermont.
This is what 16 students came up with for their project: The Pod, a mobile Tiny House designed to be hitched to any vehicle. It has its own solar system for power, and the bathroom and kitchen are supplied with rainwater. It composts human waste.
Talk about traveling light! Keep 'em coming, kids - you really got something there!