Create a fresh slave where you install VM.
Once you have the fresh slave pre-installed with VM, you can replicate it plenty of time to build your "many slaves with VM".
Remark:
With VM 1.1, VM save the configuration in files on the disk.
So you will have the same configuration for all the slave sites.
This is particular true for the Payment Method and the Shipment configuration.
In case of Payment Method, we have an extension that try to create specific config for the standard VM payment method.
See
www.jms2win.com/en/joomla-multisite?page...49&category_id=1
In case of VM 2.0, it seems that the configuration are saved in the DB and therefore the configuration should be specific to each VM.