Auto-switching Audio Widget?
And a third variant is a kind of "1x1 multi-widget", capable of holding other widgets, and expanding to their size when opened. There are several of those "widget folders" available, see e.g. Widget Folder or Widget Container (there might be more of them, but those are the two I was able to find short-term). Then each of your widgets consumes just 1x1 when not used, and the one you use opens on top of them.

To make it more plastic and better understandable:

 
Widget Container: All closed, weather opened (click images to enlarge)

The first screenshot shows 4 closed "widget containers" (the green ones). In the second screenshot, the "Weather Container" was opened, and here covers  4x4, i.e. the entire screen.

Admitted, not the most beautiful, but a practical solution to your problem ;)