Michelle Kaufmann has updated the Glidehouse to include a second story. Check out the renderings at LiveModern.com:
"Glidehouse 2 builds on the successful approach of the Glidehouse to offer affordable clean, green living on an urban lot. The 2-story Glidehouse is designed for smaller or urban lots, but also can be deployed to help preserve views from a hillside. The second story can orient the bedroom windows at the ends, or facing out. The Glidehouse 2 stacks two modules, each 15'6" x 54', to create a 3-bedroom, 2.5-bath, 1,674 sf home. A basement/garage foundation can also be easily engineered."
[Thanks, Doug]
Link: Glidehouse 2 (LiveModern)
Related: Glidehouse (Land+Living)