If your sites and applications are growing fast, then do consider the Enterprise plan - a top-quality Linux hosting package from Melton Hosting.
The plan comes with unlimited domains, unlimited emails, and unlimited MySQL and PostgreSQL databases. Also ensured are full SHH access to the server and 1 free dedicated IP address.
The service comes with 24x7 technical support and is backed up by a 99.9% service uptime guarantee. You can also request your money back within 30 days of signup.