[reeses]

Something very similar to this has been used in the military to "bridge" network barriers at differing security levels. The US Navy uses "SDR" (Secure Data Replication) to transfer content under control.

You could get all stuxnet and exploit the various applications (such as the components that inspect zipped content), but the transport itself is a simple file copy over a bitstream. You could do the same thing with kermit and uuencode a bit more easily.