I just made a quick demo video of Overland Navigator. Hopefully you guys find it helpful. Please let us know if you have any questions or want to suggest features.
I've also uploaded a few photos to my album of some of our customer installs. They illustrate some of the various hardware options available. The new 7-10" UMPC tablets and Netbook computers running WindowsXP are ideal ($350-$1800). They are big enough to really show the maps, but small enough to not interfere with passenger comfort.
I personally use a sunlight visible semi-ruggedized UMPC on a RAM mount in my truck and love it (attached pictures).