I run a hosting system - many websites over a few machines. I'd like to provide SilverStripe as the CMS system to use (tried Joomla - hate it). I only want to provide each website instance with what it actually needs and have as much common stuff centralised - to save space, make updates easier - etc. Whats the best way to go? I wrote my own 'Virtual-Host' manager (long before C-Panel was in existence) so modifying it is easy. I'll add a tick-box that will signify the user wants to use SS - so then do I symlink files into the users space, copy everything or use the Subsite module? I currently create a (php) index in the empty website - and need to understand the best way to extend this - ie copying (symlink?) in a 'template' of files would be trivial. What do people suggest.

This is Gentoo Linux, LAMP - etc.
Just wish SS was properly emerge-able....