Hi,
I have start Web_application_package_guidelines.
http://wiki.archlinux.org/index.php/Web_application_package_guidelines
I suggest to discuss and improve our web packaging standard.
PS. to avoid discussion about webapps useless.
There are (at least) - phpmyadmin - phpldapadmin - phppgadmin which have no need in multiple instances on different virtual hosts and useful even on localhost.