I haven’t determined the extent of file management tools for upcoming releases. Probably the first batch will be around R+J and XMP file extension flexibility (and possibly writing XMP into the original).
Having multiple XMP files is possible, but I think it would probably create a bunch of problems. If the point of duplication is to be able to edit an image more than one way, then I have a better approach in mind, but again, that’s in the future.