I just found this page, and I figured I'd add my results to the mix as a way of saying thank you.

I installed on my N810 via the deb packages and with downloaded bin maps from OSM. That went fine, editing the navit.xml file proved a little difficult so I ended up putting the edited file in a folder on mmc2. I also ran navit from the terminal prompt aka:
navit /media/mmc2/maps/navit/navit.xml
such that it ran my config file. This turned out well because I realised that if I swapped back to the terminal session, it shows debug info as it's working. With that, I managed to turn off the "demo" maps and note that the OSM map I downloaded was, in fact, working. After that, it was just a matter of having to zoom out and pan around, then back in to see my maps.

The maps look good, though I'm inside (at work - ha!) and the GPS isn't getting a fix, so I don't know if the tracking part is functional. I did note that the font size was a wee bit small for my bifocal eyes. I'm hoping I can change that.

Anyway, I'm just saying that it kinda works, that starting navit from the terminal provides useful debug info, and saying thanks for all the info everyone has posted. Oh, and thanks for the VI tips too.

David...