Virtual servers are very popular today i would like to give you few suggestions

1. Since VS are limited with resources maybe you should add option where user can choose will he install AV/Spam packages or not.

Yes, we tested iRedMail in VPS very often (OpenVZ + CentOS/Ubuntu/Debian).

System admin can disable anti-virus and anti-spam after installation complete, i think it's necessary to add option during installation.

Actually, user can modify files under iRedMail-x.y.z/conf/* to change bind address before installation, but i havn't write down the details.

1. Since VS are limited with resources maybe you should add option where user can choose will he install AV/Spam packages or not.

2. In Some virtualization solution services don't have access to 127.0.0.1 so they bind to server's IP ,maybe you can modify your script in order  your mail solution to work in this servers  too.

Thanks