chiming in late here, but the Zaurii are fine for geeks and non-geeks alike (and those who are somewhere in between, such as myself). As you've already discovered, you don't need to use the command line for some everyday tasks.
back to the command line: on the 5600, you need to download a terminal app from sharp. not sure if this is pre-installed on the 6000. as for emacs, again, not sure if that's there, but if it's not, you can find it (and tons of other apps) here:
http://www.killefiz.de/zaurus/enjoy!