The main problem with GPS systems is they are designed to be used safely indoors. That means if you want to go all Easy Rider, you are stuck using paper maps, which will easily get wet on the open road.

Forutnately, Clarion has a good solution with the DrivTrax GPS. It is designed to be waterproof, and powered on AA batteries which are good enough for 11 hours or work. It comes with a lightpen that is attached to the device, and, as you can see, attaches quite well between the handlebars.

Not sure about the price, nor the availability.

Via Akihabara News