If you run alot of MySQL database, this maybe not the best idea, but we use to do this, but it got to be too of pain.
this will include the MySQL database with each user's disc quota.
when a new database is created, IE username_dbname it is create in the /var/lib/mysql folder, IE./var/lib/mysql/username_dbname, now go into the the account's /home/username folder and create the same identical folder, IE. /home/username/username_dbname= then go back into the /var/lib/mysql folder, remove the folder, username_dbname and create symbolic link from the /home/username/username_dbname to the /var/lib/mysql, like so:
Now their database tables./data will be stored in the /home/username folder, but again, like I say, this is a pain if you manage alot of customers with MySQL. But it include their db's with their over-all disc quota.
ln -s /home/username/username_dbname username_dbname
chown -R mysql /home/username/username_dbname
But remember, if they create a db in their Cpanel, the db folder is created in the /var/lib/mysql folder, and you need to go through the process again, to create a symlink to the db.
Hope this may help