I have one observation to make. Why do so many dedicated GPS systems use a landscape display format? Based on my experience of using a PDA and bluetooth GPS system in my car, one of the most important things to me is as much knowledge of what is going to happen on the route ahead. A portrait display is always going to offer more information about the route ahead, than a landscape display.
I partially agree, but it depends on the orientation of your map. If you're using a "2D birds eye" view, you may set it to remain "North up" which then it doesn't matter if you're portrait or landscape. But agreeably, most like to have their orientation to be "Directional" which is to orient the map around your facing direction, or to use a 3D view in other cases.
I have another comment, as a motorcycle user. I am pleased that the artile author is mentioning that they will be making a model for two wheeled users. This is a market which only recently has been tapped, and if a product is introduced at the right price-point, a lot of revenue can be had.
From a few of my fellow riders, we feel that for a motorcycle GPS to be a success, it needs:
1) Weather & petroleum resistant case
2) Touchscreen usable by gloved hands
3) Alternative handlebar buttons for simplistic control in lieu of touchscreen
4) MP3 player w/ EQ
5) FM receiver for both Radio Stations & Subscription Traffic Alert routing
6) 12 Satellite connection
7) Anti Theft Lock
8) Daytime Viewable screen
9) Optional "Skins" to match the look of the cycle
10) Optional WiFi for Points Of Interest
There are many other "wants" but these are what we feel would make it a success