Glenn.  We have kicked around this idea a few times here.  But have not come up with a good way to solve for it.  We don’t have ways of introducing customization to the navigation component.  At some point we might wire it up so it listened to models.  But we have not done so yet. 

But here is an evil hack:
Build a custom object for navigation elements, and a junction object to user.  Build a skuid page that allows users to select which navigation elements they want (by creating junction object records).  Also allow users to give elements an order. 

Then build a facsimile of a navigation control using a deck.  Each card would be a navigation element.  Work on the styling so it appeared as a set of links across the top of the page.   The deck would be bound to the junction object (only returning records associated with the current user) and would be sorted order. 

Limit the model to a specific number so that it fits nicely above the page, and if there are more rows add a button that goes to a full navigation page (like the SFDC + sign). 

I’m sure there is some reason this doesn’t work - but its an idea.  Let me know what you think.