As I see it, the main issues are as follows, in no particular order...

1) Maps - No one will sell them in an openish format. Is there any hope of reverse engineering a map data CD? Most people here would be perfectly willing to buy the nav CD's if they could "rip" them to the empeg.

2) Routing algorithms - I have no idea what complexities are involved with this at all.

3) Text to Speech - Most phrases could easily be prerecorded, but street names and such can't all be.

All in all, I'd say that without an open source navigation system being used by another project, the likelyhood that everything will come together on the empeg is fairly low.

Matthew