Does anyone know of a way to customize the web page that is automatically shown when a user's bandwith is exceeded? As it stands, all that is shown is the following Apache default error message:

Bandwidth Limit Exceeded
The server is temporarily unable to service your request due to the site owner reaching his/her bandwidth limit. Please try again later.
Apache/1.3.33 Server at [websiteURL] Port 80

Except I run a reseller account in French and would like to be able to show a French page that links back to an account upgrade form. How can I do this?

1. Login to the server as root
2. type: pico -w /usr/local/cpanel/apache/mod_bwlimited.c
3. find html code and change it as you wish
4. save

Would changing that file affect all cpanel users on that server?

Since this isn't a dedicated server, I'm guessing it would. This will be a problem since all the resellers using that server want to customize these pages differently. Is this possible?

Nope
you can make custom "Bandwidth Exceeded" page only for all users on that server - not to individual