The correct name of the moss is: Isothecium myosuroides Brid.
Check the link below for images and some info with some links.
I know of no source of epiphytic moss species.
Apparently this is a northern species
Detailed info on the species

Have any friends in Washington, Oregon, or Northern California that live along the coastal regions? If so then perhaps they would have some growing on trees on their property.

Here is a link that might be useful: Isothecium myosuroides Brid.