I think this is a really cool idea.  Blaupunkt's new in-dash GPS Stereo, the new TravelPilot Rome uses the display of the CD player to show GPS information!

The 3.2 inch screen is supposed to be quite bright and has zooming functionality.  It has 64 MB of internal memory.  Maps of the UK and Ireland are available. 

Of course, you can still play your favorite CDs, MP3s, listen to FM, etc...etc...  The TravelPilot Rome could have been even cooler if it had an external USB port where I can plug in a large USB drive containing thousands of songs!