Don't know if it has been already requested as feature for maemo-mapper, and if it is feasible with the effort of one person only, but I throw it:

given the big time file operations (transfer, delete, etc.) take when lots of files are involved (and this is the case for maps in maemo-mapper) it would be hugely better have support for zip files in maemo-mapper: that is, maps should be readable/writeable into single files, so that a "delete maps" action, or a transfer from a winmapper set created to the memory card, or whatever, don't take forever. The slowdown for compression/decompression in execution should be acceptable if the prize is a faster management of the files, but I don't know if it is too much slow to be really acceptable.

At least for the reading side (which would great anyway!), a clue could be looking into the zip support of xmame and fce-ultra compiled for 770 by other cool coders on this forum.