I understand that the current phase of development can only handle pre-calculated routes (through such as MapOnUs.something),

Only through MapsOnUs, as a matter of fact, because they seem to be the only ones who can let you screen-scrape raw Lat/Long data. And as I have been complaining, MapsOnUs has some pretty awful and outdated road information. Yet it's the only one the app can use.

is there any sign of being actually able to access some live data (say, such as the map data BMW uses on their DVD navi-system)

That is the eventual goal, as the screen-scrape method is a dead end.

However, it has been a longstanding problem that there is no readily available "GOOD" map data that we can use for free. The only free data is worth exactly what you would pay for it, i.e., it's outdated and/or it doesn't contain proper one-way and intersection information. This has been the barrier to open-source routing on the empeg since the very first attempts, and remains the root of the problem to this day.

Kim Salo has a great mapping program for the empeg that relies on on-hard-disk-data, but we have only ever been able to find US map data that sucks. For instance, directions that tell you to go the wrong way up a freeway onramp, or that assume that you can turn right onto bridge over a freeway that doesn't even have an offramp.

I believe our only hope is being able to hack or reverse-engineer an existing proprietary map file format that contains good data. However then I don't think anyone would be able to relase it as open source or even take credit for the work. Not sure anyone is up to that task.

The empeg does have a very small display. Though it has no graphics device/card (?), would it be possible to connect a larger display to the machine (such as a 9-inch flat screen)..

This is answered in the empeg FAQ here. You would be better off, time and money wise, purchasing a self-contained navigation system with its own large screen.