For 40 bucks, it would be permanently glued into the mount and wired to a plug on the bike!
One prob on a bike is display visibility in daylight.
In May, Drove the Mercedes E55 AMG w/ the onboard Comand navigation;
Too cool. You are the point of the arrow inside the black circle. You can zoom way in such that on/off ramps and surface streets are mapped & named.
Way out of my price range, but the "Brit chick" voice over was great. It/She would warn of an up coming turn and voice over the (XM) stereo such that you didn't need to try to look at the screen, just follow her directions. Just program in "point A" (123 Elm Street, Lincoln, NE) to Memphis. It calculates the fastest route. It was dead on too. Who knows maybe in 5 years it will be common.
It would work great for a biker where the screen won't show in direct sunlight.