I have a vps with a dozen or so domains. In the past I have used kloxo, but cannot on my new vps. I have successfully managed to put Nginx, mySQL and php on the server and it is working well. I would like to be able to add mail servers so that I can get my emails for each domain back, but documentation around the web makes it not only look very complicated, but also it is confusing as to which software is best. I would prefer something that allows me to add an email and domain via mySQL. Any suggestions would be appreciated.
You could try using a panel such as webmin or cPanel. Its not a direct solution to your problem but it would make things easier to setup.
This is not available on my vps. Even if it were, it would not run nginx, it would default to apache bringing with it the lesser performance. Surely someone knows how to set up an independant email server, or does everyone do everything by control panel nowadays?
Use Postfix, it's available for most linux platforms, and can do everything you'll ever need plus more. Postfix's web --> http://www.postfix.org/ but it should already be available for download on your repositories.