Hey, me too!
I'm a mac fanatic, but I got a windoze box for my car pc

. Still installing it though. The only reason I'm using XP is GPS. I did however run across route 66 recently, so I'm contemplating making a switch -- is it any good? Theres also GPSy and MacGPS pro. I think all of the above run for ~$40.
You could redo a media engine app with the mac visual basic counterpart -- RealBasic. I've had some experience with this software, it seems just as easy as visual basic. If I had more time, I'd dig deeper.
What's this Sailing program? You can receive phone calls with your car PC?
Don -- what type of company you work for, interesting to hear requests for mobile mac installs..