mdeming

I've been searching this forum and the internet for a few weeks without any luck so I decided to join the forum and ask. I want to upgrade the nav on my 03 cl55. I don't want to use the blank button to do this as I may use navtv to play video at some point in the future. I've seen photos of touch screen nav etc. I just want to hit the factory nav button and have an upgraded unit; perhaps by hacking the drive somehow or replacing the guts of the unit. I don't know. I don't even know where to look. I've attached a photo of my comand unit. Any guidance would be appreciated.

best
Mdeming