So, it is now possible to have LDAP contacts merged with others. This is however not so clear for end users. How about we try to make it a little bit more clear by:

1. Use "Contacts (merged)" instead of "Contacts" folder name or sth like that.
2. Outlook has no way to mark contacts as read-only, but we could tag them with "read-only" category. I didn't tested yet if and how Outlook displays contact's categories.