Liveroof, based in Spring Lake MI, is an easily accessible source of green roof supplies. They offer many options for green roof aficionados, including a plant catalog.
http://www.liveroof.com/
http://www.liveroof.com/media/LiveRoof_Plant_Catalog.pdf
Global green roofs is another source, a little further downstate in Grand Rapids:
http://www.globalgreenroofs.com/oursystem.html
If you're ready to delve further into the potential of green roofs, the MDEQ has prepared a primer:
www.deq.state.mi.us/documents/deq-ess-p2-p2week-greenroofresources.doc
GFA continually strives to make our business practices as green as possible. Internally employees voluntarily recycle paper, batteries, computer equipment and cell phones - recycling around four 50 gallon bags of paper each week. GFA recently made a sizable donation of computer equipment to the Kingsley Area Schools, providing the schools with more computer capacity and saving the used equipment from a landfill. Other green practices include: outdated and obsolete cell phones are donated to local crisis centers for reuse as 911 phones, printed materials are prepared with an eye toward recycling by the end user.