I don't understand how Rendezvous could help in this situation. Doesn't it just provide for searching for network services on your local network? Or does it provide some sort of data transfer function I'm not aware of?

Nevermind. I see now that iTunes somehow uses Rendezvous to stream music on one computer to another. I bet that it only uses Rendezvous to find said remote computer, and another protocol to stream the music. So I think the trick is figuring out how to manually input the remote computer into iTunes. Of course, that's all speculation, including the part where I implicitly assume that Windows iTunes has this feature at all.