I dont have any way of really testing this, but I saw it done once and wonder 
how one might configure a nework to do this:

All users home directories are stored on a central server.  There is a lab of 
computer than any user can log into.  Before the user logs into the computer, 
the home directory is not there- it dynamically mounts the home directory of 
the user when they log in.  This way you only see the home directories of 
people logged into the machine, and not the thousands of other users.  This 
was done on the campus at NAU in Flagstaff, and I have not been able to get 
back to see it since I figured out how NIS/NFS works.

Jay

-- 
Jay Kline
list at slushpupie.com
http://www.slushpupie.com
--
Do not sleep in a eucalyptus tree tonight.