Has anyone worked on sites where the menu hierarchies is fairly large?
Not more than 3 levels deep, but more than 40+ menu items?

If you only list first level items in the top menu without dropdowns and you want to show children in the left section of your site, how do you do that?

As far as I know, there is still no function like getChildren() of current selected menu item. My only solution so far is to use get_page_children() – but those children are from current page, not the menu hierarchy.