Well, not coops exactly, but they do sell shed kits on their web site that a clever person could adapt. Some are wood, some are resin.
http://www.costco.com/Common/Catego...-US&hierPath=50126*50888*49273*49275*&topnav=
Phyllis
http://www.costco.com/Common/Catego...-US&hierPath=50126*50888*49273*49275*&topnav=
Phyllis
