Editing an existing view scheme so that it ignores parent view search rules, and remove all the rules from 'specify files to show' so that it shows all files in the library, then saving it, should also work. When adding a root view, you should see that view in the view selector. Select it, then edit it to suit your needs.
-marko
Tested this this morning, and it does not work.
So far, the only way I have managed to get a saved view to present itself for adding to the root is to open a .jvi file in a text editor and change its 'media type' value to 15
but, that only works if you have all four media types present in your library, Audio, Image, Video and Data. If I have the time, I'll try and get at the values for other media type combinations.
You only need one of these, because obviously, once added, you customise to your hearts content.
-marko.