Well, I went ahead and contacted PAC-Audio today asking the same questions to their tech support and I got a prompt response that I have copied below. It answers some questions, but I wasn't too excited to hear about all the pieces to make it work. Will have to keep researching.
Let me know if you find out any new information!
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Here is a list of adaptors and harnesses required for Bluetooth video in your 08 Honda Ridgeline.
VCI-HON1 video adaptor
68120 + 68825 plug and play harnesses
Tell 5000 VI Blue tooth interface with video output.
At this time there is no Nissan steering wheel adaptor for bluetooth
Tell 5000 requires it’s own microphone.
Please contact Raytell for phone compatibility
http://tellphone.com/
Thank You.
Jose J.Martinez
Technical Support
Pacific Accessory Corporation.
800 854 3133 Ext. 133

From:
Posted At: Friday, February 15, 2008 8:15 AM
Posted To: Inbox
Conversation: Raytel Tell5000vi for 2008 Honda Ridgeline RTL w/Navi
Subject: Raytel Tell5000vi for 2008 Honda Ridgeline RTL w/Navi
To Whom It May Concern:
I have been researching adding bluetooth capabilites to my 2008 Honda Ridgeline RTL with Navigation and I have continually returned to the Raytel Tell5000vi for a seemless integration look and feel however I still have some questions that I was hoping to have answered so I may continue with my research and possibly purchase.
If it isn't too much trouble could you please let me know what would be required for the most efficient straightforward installation of this product into my vehichle? I am mostly referring to the necessary harnesses but feel free to expand. This vehichle is a lease without a rear backup camera however my wife has a 2008 Honda Oddysey EXL with Navigation and rearview camera so may eventually consider putting the product in her vehichle. The intended cellphones would be an Apple iPhone and a Samsung u740. Also, can the unit use the existing navigation microphone or do I need to use the microphone that comes with the Tell5000? Will the navigation touch screen or steering wheel controls interact with the product at all? Is the screen only viewable when the phone is in use?