I bought a Garmin GPS 18 ($110) that connects to my laptop. Works great but I needed a place to set it. The first couple of times I used it I just set the laptop on the dash. Worked OK.... but just was not what I wanted. I looked around on the net and saw a Jotto Desk... Neat item but the cost ran from $189 up. So, decided to build one.
I used some exhaust tubing and a TV tray. After some cutting, drilling, welding and paint I have want I wanted for about $20. The unit is adjustable up/down and swivels so the co-pilot can use it. This is a prototype so it is probably over designed and over built :-). With the addition of 2 more pieces of tubing I could have tilt and lateral adjustment.
I have posted build photos and some doucumentation on my Yahoo Photo page. Follow the link in my signature.
Here are a couple of pics to get started.