The default global completions file that comes with Mac OS X uses /etc/hosts to get a list of hostnames. This isn't terribly useful since that file generally never contains anything useful (and there is a comment in the completions file suggesting that it be replaced with something smarter).
Create a file in /usr/local/share/ called common_hosts (make sure it is world readable - 'chmod 644'). Inside this file, list common hostnames (on seperate lines) that you commonly have to type out.
Now edit line line 83 of the global completions file (/usr/share/init/tcsh/completions) so that it refers to the new /usr/local/share/common_hosts file instead of /etc/hosts. i.e.: alias list_all_hostnames 'grep -v "^#" /usr/local/share/common_hosts'
Say your common_hosts file contains the hostname:
dhcp-user.192.168.1.1.somehost.edu
If you need to ssh or that host you could just type:
ssh dhcp[tab]
And the shell will expand the hostname.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20011127132046260