Use case : We want to restrict certain users to only be able to build VMs from templates and not be allowed to customize anything apart from the name and the timezone. I'd suggest that we have a new permission for creating 'custom' VMs.
this is far from trivial, it means we need to give a user a permission to create VM without getting the VM Owner role on it, only the VMLimitedOwner (run, delete) or something like that. and even then, prevent run once to that users, etc.
Closing - let's handle as part of 3.2 templates (instance types, etc) *** This bug has been marked as a duplicate of bug 874328 ***