A bit of news.
A lot of development has been done. There's now a really usable OpenGL GUI : http://www.kazer.org/navit/navit_gl_fixed_fonts.mpg
There's also a huge work begin done on the modular_map branch. Garmin map support was added, and routing is working in this branch too. Still the navigation has to be fixed in this branch (but is working fine in the main branch, as you can see in the video).
Comments / criticisms / ideas welcome