I would like 2 ways to handle error pages, Either per domain let them edit the error pages in there CP or, let the server admin in the main CP set error pages.
This is nice for the people out there that don’t know how to use other means to custimize them.
It’s one of those things that they will pribably get around to eventually, but have a lot of other things ontheir plates first 
Currently you as the admin can configure this by hand of course (even on a server wide basis) by editing /etc/httld.conf but the easiest way for a user to do this is with a .httpaccess file so they don’t have to edit any config files.
This is nice for the people out there that don’t know how to use other means to custimize them.
I agree, in the meantime I’d setup default error documents in your main httpd.conf (i.e. 404.html) so that any client who asks you can simply be told to upload a 404.html into their directory and it’ll work.
Chris