Where / how can I set the standard listview layout that a new user will see for any given module?
Admin > Studio > Module > Layouts > List View
True 
What’s missing there is the sorting, which is quite crucial imho. Any idea where this can be set?
I’ve also always wondered how I could create a saved listview layout and make it available to all users.
If you create a changed view in Studio, it should be available to all users, I think.
But if you need to edit the file directly, to change the default sort order, for example, I think you can do it from the listviewdefs.
This post should take you to the right place:
http://urdhva-tech.blogspot.pt/2013/03/concate-2-fields-in-list-view-without.html