I know for a fact that it is possible to harvest maps from www.eniro.se. I have made a Perl script that is a bit shabby but does the job. It also has the ability to download a square area if you specify the length in meters. One thing about www.eniro.se, they are not using the WGS84 system used in a gps device. They use the official Swedish RT90 2-dimensional system, There are ways to transpose between RT90 and SWEREF99 which is almost precisely applicable on WGS84. But i haven't yet been able to do so, to much school at the moment . But i have used Lantmäteriets web-converter to cheat . It checks the WGS84 coordinates and gives the RT90 coordinates back.

My script works with GpsDrive, it should be possible to adapt it to maemo-mapper but i don't know if it should be integrated with maemo-mapper because of the small number of users in Sweden and the extra conversion between RT90 and WGS84. Just a lot of code not really used by so many people.

Maybe the map-downloading part of maemo-mapper could be lifted out in to a small separate replaceable executable?

EDIT: Lantmäteriet -> Swedish geographic survey office