Question of OEM Radio / Nav

I am looking to get a 2007 2006 Hybrid. My question concerns the radio / nav combinations. It seems to me that the JBL 6 CD changer is not installed with the Nav system. Is this true or are there vehicles out there with the Nav and 6 CD JBL system?

The reason I am asking is that I want to be able to add an interface for an IPOD after getting the vehicle. I believe that the interface is available for the JBL 6 Disc system but I am not sure that it is available for the JBL and NAV combination.

So if the community could provide some informaiton it would be helpful.