For anyone who is interested, here's a tarball with a map of the second world*, as it turned out in the end:
[Mirrored below, so taken out from here]
It's divided into the various supergrids for practical reasons. I tried combining them all into one huge image (35000x35000 pixels) but the only program I could find which was at all capable of opening it without erroring out or crashing was the Gimp, and even that took 15 minutes or so to load the image. Each supergrid is 5000x5000 pixels. There's also a file displaying the civilization levels over the map. The RoB is at pixel 2000, 2000 in the file sg-0-0-map.png.
The file is 18 MB large. Keep in mind that it's on the same server as everything else, so bandwidth will suck right now, and it will drain everything else, so please download it responsibly. If someone can mirror it, please do. :)
* It's actually the fifth world, but I wouldn't expect you to know about that. ;)