Multi Site and using a Navigation Control

I am looking at Multi-Site as a possibility for our use and I had a question. 
Is there a way to make the pages on one site be shown on another?

I have seen 2 options to use in this respect.
1) The Site Selector drop down.  Don't think that will suit our needs.
2) The Redirect page option when creating pages on the site I want the other sites pages to be shown.  This is "workable", but will not (based on permissions) show/hide the page when the user doesn't have the ability to get to it. 

Is the Sitefinity development team working on something related to this for an upcoming release?
Or should I consider creating a custom navigation control?  If so, how would I go about getting the right data to show? 

I would greatly appreciate the help.

Thanks,
David