Ralkage this is kind of the idea.
For an extension like Flagrow Ads for example, for ads that don't repeat, you could delegate positioning to this extension. So you'd have for example "sidebar ad", with a default position, and no position related settings in the Ads extension. Then you can use this extension to change where exactly it's rendered between other items of the sidebar.
For standalone components that don't depend on the object that outputs the itemlist, we can even allow inserting those components "widget style". For example an online users list that loads its data independently wherever it's inserted in the app. Such an extension could expose its component with some sort of widget API, then this extension can let you place one or multiple instances of that widget anywhere there's an ItemList.
