As for AmigaDE, if they have a Linux port I don't see any reason why AI couldn't cross compile it to the Zaurus with a few twiddles. If DE isn't on the Zaurus, I would blame AI
DE is on the zaurus, you can even download it from somewhere on Sharp's site I think.
Thing is Sharp didnt include it with the initial zaurus package and dont support you if you install it.
The above is just from my memory of news items read here over the last few months. Perhaps someone who has a Zaurus could tell us of their DE experiences.
Pteppic