Hi,
All the menus do is render a heiarchal list of ul and li, the styling comes from css, so if you have a third party menu that can somehow consume that list from the page then it should be able to use the existing rendering.
Maybe whats throwing you off is that many of the skins have split the menu up to have a horizontal top level menu then a vertical menu for pages at deeper levels so in those skins the whole sitemap is not in a single list. But there are other skins where the whole tree renders as a single hierarchal list, see mitchinson-earth,jsavard-mojoportal and others.
Best,
Joe