Add support for sufixes. and [DOMAIN_NAME] and [DOMAINID] var
Have only option to use prefix. why not choose beetween prefix and sufix for database name, client, ftp and ssh.
Another sugestion:
Use of domain name or domain id turns more easy move sites beetween clients. move directory re-links and run a chown ower of files recursive.
can make user names for ssh and ftp like this: user#domain.com or using @ name@sufix sufix can be DOMAIN NAME or DOMAIN ID.
Database user using DOMAINID and choose a domain of database with a combobox. My opinion it´s more sense link database to a domain not for a client. turns more easy pass a database and sites beetween clients.
Ispconfig modules are independent, using domain id/domain name it´s a interessant idea for some features.
Im using ispconfig3 on prodution enviroment and i think this idea using it.