I can’t find anything on this by Googling.
I want to move to another host because of quality issues with my current provider. Rather than setting up Virtualmin on a new VPS and migrating the virtual servers through backup and restore, I was wondering if I can just start with a bare Centos installation and move everything?
Howdy,
The easiest way to migrate is to start with a fresh OS install, run the Virtualmin installer, then to import your backups.
Instructions for performing a migration are here:
Theoretically, that’s possible. In practice, it’s probably going to be more hassle than installing Virtualmin freshly and restoring domain backups. 
The only way I see for doing this is, provided the OS on your former and new VPS host are exactly identical, is booting your VPS (if that’s even possible) from a kind of rescue medium / network boot, partition and format the virtual disk, and use rsync to copy all files over. Then you need to get the boot sector and grub onto the thing.
If both your former and new VPS hoster were using the same virtualization system (e.g. VMware), and you had access to the virtual disk files, you could copy those over. But on a mass hoster, you usually don’t get that kind of access. If you were MY customer, I could do that for you. 
Thanks for all the help. I thought it would be worth asking as I couldn’t find anything. I’ll go start from scratch with a centos install.
you might consider installing virtualbox.org and install a test centOS installation - then run a mock conversion there.
virtualmin/webmin has some very powerful migration tools built right in.