Selector for childless pages (navigationOptions)

[retropele]

I'd love to make a navigation menu where I can initiate a breadcrumb style navigation/collapsible menu depending on whether the page has children, or is childless.

I think displaying only parents is technically possible because of the navigationOptions for parents - though I'd love to use a macro to insert more than a class, and a couple lines of HTML for parent pages to make a HTML only collapsible menu. (That may already be possible though, I am just ignorant.)

A childless page selector would be great, because then I would be able to manually create menus for parents, and then show all childless pages external to that automatically.

As it stands (as far as I know!), I don't know of any way to display only childless pages. Is this correct?

Sorry if this is a duplicate issue/request, I really did look around.