Been meaning to build a carrier for plywood for some time. Its hard to get your arms around a sheet of plywood to carry it. The author here built a carrier out of scrape, and put a caster on the bottom. Good idea (not so sure I would build the 2 wheel carrier version thought).
http://tombuildsstuff.blogspot.com/2011/10/diy-drywallplywood-panel-carrier.html