I'm just starting to dig into SSH right now...
but from what I've gathered so far, yes you should be able to set up that server through a SSH tunnel. You may need to get the specifics from one of the Gurus around here or get ahold of one of the manuals on SSH, but the basics are that you'll set up a SSH server (or OpenSSH or whatever is available for your system), then set up a PPP tunnel (for Linux you'd use pppd), then lastly your game server. There is a telnet client that's supposed to support SSH for Windows, so you may not have to do the same thing on the client machine.
Obviously this wouldn't be the best setup if you want Joe Offthestreet to join in by word of mouth, but it should keep Ima Hacker away.
~~~)-Steven----
"I want you to remember that no bastard ever won a war by dying for his country.
He won it by making the other poor dumb bastard die for his country..."
General George S. Patton
