This is already implemented. To load this from the skin folder and support widgets, you need to make it a collection.
So...
The way to display widgets on a homepage is to use a "Main" collection with a "Special font page"... which will have the container you need.

I am pretty sure you are mistaken and are misunderstanding. Perhaps the (I sense a scolding coming on since I didn't do it from the start) screenshot will help to align our thoughts.

This is a file that gets displayed if a site has no default collection defined.

Thanks for the screenshots, always good to have them.

In this case I think my answer still stands: the way to configure the "default" page is to create a "default" collection and set it as default collection. Don't put posts into that collection, just use its homepage to arrange widgets.