Aside from using a multi domain SSL certificate is it possible to have the mail server and usermin use a different certificate for different domains (the different domains in questions are using different IP addresses).
It has been implemented in apache but wondered if it had been achieved in virtualmin.
You can, so long as you have more than one IP address.
Other services do support that, but it doesn’t work the way it does in Apache. If you put a domain on it’s own IP, you can then copy that particular SSL certificate into Postfix, Dovecot, Webmin, and Usermin – just on that one IP.
You can copy that in Server Configuration -> Manage SSL Certificates.
I tried that and it just copied the certificate to every site.
Also will you ever offer a plan that allows you to spread your 10 domains over multiple servers.