Password protect entry for specific member(s)?

I have a client that needs to password protect the contents of an entry.

Is there a way to create a Member field (or fieldtype) that I can use in a Publish Entry page? That way an author can choose a member from that field (based on registered members) and that page is password protected and only viewable by the member(s) they selected in that field. I realize I’d have to create the template logic that would display only the contents if that member is logged in.

Does this make sense? Help is greatly appreciated!

Michael