How to easily create and reference a node / entity during creation of another one?
The References dialog module might be an option (if you're using the references project).


  This module extends reference fields like the user and node reference fields by adding links to add, edit and search for references through a dialog. This allows for a workflow where the user can create all the references to a node at the same time as she is creating it, a process which sometimes get's a bit backwards, when a user for instance needs to create all the facts for an article.


It doesn't do exactly what you've described, but it's pretty close.