Which is the new functionality provided by your new plugin? Remko added a cool extension to VCards so that you can hook up listeners and react when a vCard was created/updated/deleted. I still need to review and include his changes.
BTW, vCards stored in the DB unlike LDAP-vCards do not require any configuration or setup. Currently, vCard logic resides in VCardManager and DefaultVCardProvider. You should be able to get everything you need from those classes.