Hmm, unfortunately I don’t think there’s a good workaround right now for not-so-unique names.
Obviously if the lists are together and not too long, you can do drag and drop.
Another idea is to port the parent: and ancestor: search ops over to this move item dialog (see Find search terms in parent nodes as well). That way you can search them based on which project it belongs to (e.g. done parent:oude).