HL7 Security

I can't find much in the way of security for HL7 (health information interchange via tcp/ip streaming).  Seems like vendors are relying on VPNs over the internet and then exposing themselves in the DMZ and/or soft pink underbelly of private networks.  

Does anyone know of anything like the following:

1.  secure HL7 projects--e.g. for developing standards or practices for secure end-to-end HL7 communications.
2.  HL7 over SSH or SSL, applications/vendors that do this, or projects devoted to developing standards.
3.  a firewall with Deep Packet Inspection, protocol inspection/verification, or any other HL7 specific security.
4.  an application layer proxy for HL7

Thanks,
--Patrick Darden