Are you a Ravelry member? If so, you can search for the yarn and see who has it in their stash. Anyone who has marked their yarn as "up for sale or trade" will show up first. Try PMing those guys first, and if nothing, then try PMing someone who just has it in their stash. I have a few things in my stash that aren't marked as for sale, but I would be willing to part with them.
I didn't search for it but I bet someone has some!
Or try a sub... Either way, good luck!