For internal outages I've created two scripts on each of the proxy servers. /etc/httpd/outage/outage.sh and /etc/httpd/outage/outage-over.shThey're pretty self explanatory. Basically though they stop httpd and start up a special instance. Configs, html and images are all self contained in /etc/httpd/outage/ so as long as that dir exists and apache is installed, the outage page should be viewable.
-Mike