Here's an interesting guide on building a Car PC. This is of interest to Smart Home entusiasts too as many of the requirements that make an idea car pc (multimedia, touchscreen, network, small form factor & silent opperation) make these systems idea for many home automation and media player roles too...
"Car PC users need to get to their applications fast and with a minimum of interaction. So keyboards and mice, while handy for occasional work in the car, are of limited use in a car. Instead, car PCs should rely on touch screens and software interfaces with "skins" that let users access their apps quickly and safely. In car lingo, a touch screen works like a "head unit," providing access to music selection or a GPS. A major goal of a car PC is to replace the vehicle's head unit with a touch screen that will act as GPS, CD player, radio and the like.
Skins used with voice-recognition software can also provide safe and a mostly hands-free method of working with applications. Applications like RoadRunner and SKINbedder work with NaviVoice voice recognition to provide quick access to applications with a minimum of driver involvement. In the screenshot below, you can see how NaviVoice helps to integrate voice activated GPS with media playing and other applications, making GPS functions available quickly and safely with a one-word command..
