This is a feature request.
PODS has what they call "Flexible Relationships" which allows a user to add/edit a related item(s) from the main post screen.
For example, if Books are related to Authors, a user can add/edit Authors while on the Books screen without leaving the Books screen.
They essentially do this by opening the Authors' edit screens in a popup and return you back to the Books screen when you're finished.
See a video demo here: https://www.youtube.com/watch?v=V8c067GAEcA
My request is to add this functionality to Metabox. It makes working with relationships much easier and faster.