Samsung has come out with the Q1 which is probably smaller than the Motion tablet. I had a play with it at Dixons duty free a few days ago and it is excellent. It is also a good size for aviation charting and costs about £800.
My Ipaq is also good with memory map. You can see the screen in direct sunlight and I have it linked to a bluetooth GPS receiver.
But if you want to go the whole hog this would be nice...
http://www.mc.com/vistanav/index.cfm..however I dopubt the database works in Europe.....