There are a number of front ends used for Mac based carputers, unfortunately most of them are either abandoned projects, lacking in features or polish, or otherwise not quite exactly what I wanted. My main objective was simply to use this as a big, fancy iPod, my old click-wheel iPod just isn't quite cutting it anymore in the car. Something that used cover flow would be ideal, easy to navigate, clean interface, in short, what I was looking for was basically already part of the Mac OS, Front Row.
My main issue with Front Row, though, was that my plan was to use a touchscreen interface for the carputer, and Front Row did not allow for such use, it used keyboard input only, or the Apple IR remote, which is basically a remote keyboard, mouse or similar inputs aren't used. What I wanted, ideally, would have been some way to remap the touchscreen input, so that I could touch the top or bottom of the display for up/down arrows, left/right sides for left/right, etc. Unfortunately, I wasn't able to come up with any software that would let me capture inputs this way, so I was back to square one.
A number of folks had recommended the Griffin PowerMate for controlling Front Row, but I wasn't terribly happy with that solution either. At this point, my plan is to use a Logitech Precision Gamepad to control the action, and the USB Overdrive software to remap the controls for what I need.
After some testing, I found that I really only need four keystrokes, up, down, return, and escape to do all I need done in Front Row. My plan for phase two of this project is to disassemble the gamepad, remove the d-pad portion of the controller (lots of soldering and hacking there) and fabricate a new housing for this that would be placed at the steering wheel for easy access, that is, unless some better idea comes along.
So, with the controlling part done, the next thing I needed done in software was a way to keep my tunes in sync with my home system. Time to start coding...