I proposed this new feature at the Glasgow Moot and it was voted third by participants. The addition of stealth mode for activities and resources recognises how often teachers want students to access an activity from within a book, or a page or in a label with say Tabs added to it. However this is not simple for teachers are not very familiar with Moodle. What is being requested is a simple way to do this, so that in a book, for example, the add activity is available.
Practically this would be easiest to implement if it is seen as a way of automatically creating a stealth activity in the containing section for that book resources and placing a link to the activity into the book, along with the edit/delete functions.
I might be able to get a little funding from my employer to sponsor a developer to take this forward, something we have previously done with plugins.