Display each menu level as its own separate level; continue to display menu on bottom level with no children

Hello,

I am working on configuring my menus to have specific behavior. By way of illustration, please assume the following menu structure:

Parent
-- Child 1
---- Sub-child 1
---- Sub-child 2
---- Sub-child 3
-- Child 2
-- Child 3

1. When visiting the Parent page, I would like the menu to display as follows:

-- Child 1
-- Child 2
-- Child 3

2. When visiting Child 1, I would like the menu to display as follows:

---- Sub-child 1
---- Sub-child 2
---- Sub-child 3

3. When visiting any of the Sub-child pages without children, I would like the menu to continue to display all links at that level, thus:

---- Sub-child 1
---- Sub-child 2
---- Sub-child 3

I note that menu_block was released as per http://drupal.org/node/345552 to hide the menu altogether if the current page (Sub-child x in my example structure) has no children. Is it possible to, via the admin, restore this behavior? Has a patch been produced to restore this functionality? Thank you for any help you can provide.

Best,
Peter