Border / Frame Tool

It would be awesome to have a border tool, where you can add an external color frame, with various size and color around the picture, the only way to do it at the moment is to export a tiff and do it in photoshop, but it would save a lot of disk space to be able to do it in the library with a variant and not to have a tiff export for each pictures. I've seen lot of requests of this kind on forums since years, but its never been added.