For anyone that is interested.
I just bought one of these. Itís not intended for motorcycle use (not waterproof) but works brilliantly. The suction cup mount works on both my screen or the tank. Itís easy to use with gloved hands and is fast and accurate. It comes preloaded with all of N. America. If it starts to rain simply unclip from the mount Ė it takes a couple of seconds Ė or put a Ziploc bag over it. Lasts for up to eight hours on an internal rechargeable battery, so if you donít want to wire it to the bike you donít have to.
Best of all, you can get them for as little as $170 on the internet. I bought mine from Circuit City in Bellingham ($224). Even at that price itís an absolute bargainÖ.