One of the things I like with open-embedded on the 3100 is that it uses a microdrive partition for the operating system -- no ipkg-link, no symlinking directories to the flash-storage, no worries about filling up the flash. The downside is that the flash is unused.
For pdaXrom it would be cool if someone could develop a system that makes use of unionfs. This way it could be used with all devices (not just those with microdrives) to extend the filesystem onto another memory card. And because unionfs is an overlay, when it is running, you can delete or modify files in flash and it is reflected in the overlay -- not in the physical flash. Boot without the unionfs card or unionfs turned on and the flash is back in your default state.
Anyway, someone seems to have had success with unionfs on the Noka 770, so it should be possible for the zaurus:
http://www.hczim.de/software/mmc-unionfs.html
