i just received iphone 5 and with this new lighting cable , we arent able to acess video files from iphone even after 30 pin adapter is used. So i was wondering if anyone on this forum ever tried hooking up an apple tv to their navaigation unit? .. life would be much easier if that was possible..

Not directly; the Apple TV outputs HDMI and/or Component. You could however use a converter, I've seen it done.

I have that done in my truck. HDMI to analog (red white yellow) video converter. Be careful when buying most require ac volts. But it Does work well for me. Apple TV allows you to use airplay mirroring. That also works great.