Thanx everyone for helping to make a point I tried to stress in my seminar this summer. Be creative. I was teaching n rooting cuttings, but the point was that everyone finds a different way to do it, as long as they understand the principles. My friend uses the van in his front driveway to keep his cuttings warm. I don't have a van, so I do something different. A "recipe" approach is fine, but understanding the principles ultimately give you more adaptability and success.
So, that is a long way of saying, that I learned some new ideas and sources for Vermiculite, and clearly there is more than one solution, even though it was easy for me to go do Home Depot.