UI suggestion: Database-style select existing or new content.

I’d like to see a control that allows me to Select from a list of existing content items and if none match what I want to select, then I could select ‘New…’ and a pop-up would open or an iFrame would become visible for creating a new content item of the type used in that control.

In the settings for the control, I’d want to be able to pick the content type, and the field to display. the value would be the contentid of the chosen item.

If I chose to create a new item, then I would expect the list to refresh after saving the new item.

Basically, I want a way to create relationships between items in a structured way without using Active Assembly.