Java EE (Java Enterprise Edition) General Discussion

Hi,
I am trying to design a RMI-J2EE architecture
- The clients are Swing applications which communicate to the server via RMI.
- The backend is a combination of xml-rpc based web-services and EJB components.

What is an efficient scalable design for the RMI clients to access the backend.
These are the constraints
- Session handling is required
- There may be firewalls so HTTP Tunneling may be required.
- Performance, security and scalability are critical

Essentially I am looking for a good J2EE design using Swing/RMI rather than HTML/JSP

Regards
George