Now that the admin has been split out into a separate module in 4.0, the only way to overload the templates is to have a module that sits above it alphabetically e.g _my-custom-cms/templates/SilverStripe/Admin/Includes/*.ss will override the admin templates, but z-my-custom-cms will not.
Is there a way to force the admin to use a template regardless of it's folder name?
Cheers!