I set up a binary server on one of my real machines to service a vbox hosted on it. It seems to work okay, but both firefox and thunderbird are re-emerging ... I suspect that they changed between when I did a --sync on the host and a --sync on the client.
I can't see any problem with configuring the machines in the other direction, as well, so I can "upload" the compiled firefox and thunderbird to the host. Any thoughts?