Flat Roofing solutions-
EPDM rubber membrane
the rubber is great for residencial and small commercial... maybe a way to use the container as a building as a site?
http://www.flatroofsolutions.com/
this a company that deals with EPDM roofing. this is a link to the portion of their site that discusses the green qualities of the product.
Aerospace fabrics
http://www.3m.com/market/industrial/ceramics/materials/fabric_312_aero.html
GORE™ TENARA® Architectural Fabric
http://www.gore.com/en_xx/products/fabrics/architectural/gore_tenara_textile_products.html
Sharkskin Ultra™ Roof Underlayment
creates a great moisture barrier
http://buildingforhealth.com/proddetail.php?prod=SURU
images:
Structures for the roofing
here are simple metal roofing trusses that are built to be outside although they are not that big.
http://www.clearspan.com/farm/supplies/home
http://www.sheltersofamerica.com/productdetails.php?productid=139&id=6
Velco product!
http://www.fastenation.com/category.php?id=254&crumbs=145,254