The idea has partially been discussed elsewhere. I just like to add to such ideas:
Themes and styles already help us a lot. There can be several themes and styles for one layout, and the same theme can be applied to another layout. And there are multiple themes.
Here we go a step further adding Master layouts where one master layout could also be the master of another master layout. So, there will be inheritance from master layout to other master layouts and finally to the child layout (which are the layouts we are currently working with).
Then the table occurrence layouts - as we know them - will inherit themes and styles and layout objects defined in the master layouts.
Changing such objects and styles on the master layout will change same objects, styles and properties on the child layouts automatically.
To express it in other words: The "master-master" layout for example contains a logo of the application owner, or an application icon, and very basic layout structures defining bars, panes, etc. using graphics and everything that can be shared between layouts without having to define dependencies with underlying tables. Then a master layout inheriting for the master-master-layout would add some more specific graphical elements which might allow to see that this layout belongs to a certain group of layouts, or a certain module inside the application. FInally the child layout inherits all these visual elements and those objects which can be shared accross layouts.
HUGE SAVING IN TIME WORKING WITH LAYOUTS