How do you envision this actually working, in practice?
For example, Embarcadero’s RAD Studio recognizes different screen sizes and form factors on a per-device basis. So, for any Form, after defining your “default” or “generic” layout, you can also derive alternate layouts, for use on devices with smaller or differently-oriented screens.
When it comes time to actually build & run the application, then the builder chooses a suitable layout, for each Form.