Recently I've been hit up a few times for resources on virtual economy design. I haven't written that paper yet, nor has the other most prominent academic virtual economy guru, Vili Lehdonvirta. No, instead we decided to write a book on the subject, which should be coming out next year. Meanwhile, though, here are some links that will help.
And finally, I would keep a close eye on Valve Economics and Yanis Varoufakis