In a nutshell, here's most of what I did.
WIKINAME=syswiki
mkdir -p /var/www/wikifarm
mkdir -p /var/www/wikifarm/$WIKINAME
cd /var/www/wikifarm/$WIKINAME
cp -f -pur /var/www/wiki/* .
ln -s /usr/share/mediawiki/*.php .
ln -s /usr/share/mediawiki/*.php5 .
ln -s /usr/share/mediawiki/extensions .
ln -s /usr/share/mediawiki/includes .
ln -s /usr/share/mediawiki/skins .
ln -s /usr/share/mediawiki/languages .
ln -s /usr/share/mediawiki/locale .
ln -s /usr/share/mediawiki/serialized .
ln -s /usr/share/mediawiki/maintenance/ .
chown -R apache:apache *
unset WIKINAME
There's more to it than that, but that's most of it. (And stuff I
don't need to sanitize to send out).
stahnma