Sorry this is slow in responding. I have done the command Pete suggested

Q ***GUI*** * for *@*

We have 2000 lists, and I forget how many subscribers (270k individual
names in our signup files). It returned a 50M file, and ran for awhile
(sorry, I forget how long- I think on the order of 5 minutes). We're on a
1Ghz Pentium, so it's not a high powered box. So if you do this outside of
normal business hours, mail will be delayed a bit, and people won't get
response out of the web interface.  But it's very very doable.

-- Syracuse University Listserv List Manager
-- Listserv webpage: http://listserv.syr.edu
-- Web access to List Archives, Manuals, and List Management for Owners.