Material Resource Listings or Sharing Green Products Order

We are looking to avoid PolyIso insulation and found a 1" stone wool rigid drain board made by Roxul. The problem is there is a minimum order of 1000 sq. ft and we only need approximately 1/3 of that. Does anyone know if there is a local materials exchange where we could try to sell the rest? Is there a means of finding others interested in "green products" purchasing to go in on a group order?

Thanks in advance for any advice.