A new program called RendezvousVPN is now available from Phillippe Hauser that creates a Rendezvous tunnel between two networks. It's unclear to me whether it tunnels all of the traffic or just the Rendezvous traffic, but my guess is the former, as it would be more difficult to get around NAT, etc. otherwise. The program has a "unique" licensing scheme that charges per service, per node pair. So, if you just want iTunes sharing, it's a pretty reasonable $7.99, but for the whole suite, it's closer to $150 per pair. Although not unreasonable, especially when trying to differentiate between business and consumer users, it does create a problem where the user must have a priori knowledge of which services they want to use and no unsupported services are alive.

Yes, Amanda, I'll start thinking about that project again...