I agree that this would be useful. Assembling a navigation bar from the existing controls is more work than it should be, especially once you need a hamburger menu.
I've accepted and logged a feature request for a Web NavigationBar control. The planned control will support a brand caption and optional link, named items, dropdown submenus, separators, system symbols, a current-page indicator and optional sticky positioning.
By default, it will collapse into a hamburger menu on small screens or when the items don't fit the available width. You'll also be able to choose the collapse behaviour explicitly.
You'll configure the items in the Web designer and modify them from code. Ordinary links will retain normal browser behaviour, while action items will have their own Pressed handlers, so showing another Objo WebPage will be straightforward. Keyboard and screen-reader support are part of the plan too.