Car computer - anyone done it?
 

I want to integrate a computer into the car which will allow me to do several things:

1) Play music like my MP3 collection from a hard drive, preferrably through my stock Monsoon sound system.
2) Provide satellite navigation with audio cues, again preferrably through my stock sound system.
3) Conduct live OBD II monitoring/recording
4) Record live performance data, like through a GTech or similar
5) Integrate the above data with multilple video streams (of me at a roadrace or auto-X, etc)
6) Allow me to get my emails, instant messages, surf the web, videoteleconferencing, etc all while conducting daily driving, (stoplights, etc.)
7) Essentially turn my '02 WS6 into a modern KITT using off-the shelf 2007 technology.

Keys to success include:

Include a startup/shutdown control to not drain the battery.

Minimize moving parts to reduce the chance of crash or failure from vibration.

Minimize the physical size and weight of the install.

the computer to be mostly hidden, and the parts exposed look factory or professionally installed.

minimize my cost by using a lot of stuff I already have and limiting my purchases to off-the shelf technology

use a touchscreen, a text-to speech engine and voice recognition / voice command software to minimize the need for keyboard and mouse and minimize my time looking at the display while maximizing my productivity.

use wireless keyboard, mouse and listening devices when necessary to reduce hassle of wires. Must be easily stowable when not being used.

Have easily accessible ports for expansion, update, data transfer and communication, (USB, SD card slot, CD/DVD-ROM, etc.)

Can anyone point me in the right direction? Does the Monsoon head unit include an aux sound port? Thanks.