I needed a solution to add new values to an existing shuttle on user demand. That means that the user should be able to add values in a shuttle with a text input. For that mather I created a plugin which allows to manipulate a shuttle with additional values.
To use this plugin you need to create a regular “Shuttle” item on a page and the plugin item. In the plugin configuration set the shuttle item like in the picture below and that’s it. Free to use under GPL. Download the shuttle extender. Or try a demo (login: demo/demo)