Jim,
I have Intravee + KCA-420i setup as well, and I put all units in my trunk.
Stock cables which came with Alpine KCA-420i were not long enough to run the unit to front or under the seat.
However, I have no problem to having my Ipod in my trunk since I have full Ipod control through Nav screen.
Back to your question anyway, there is an extension cable for KCA-420i.
You can get it from ebay,
http://cgi.ebay.com/ws/eBayISAPI.dll...MEWA:IT&ih=019,
This cable connects Intravee unit and KCA-420i unit, 15ft shouldl be long enough to run your KCA-420i unit to front.
Good luck
