Several years ago I worked at Sharp's research lab in Oxford, UK, where I did scientific research and development of image processing and computer vision for novel displays including 3D displays. One of my colleagues suggested getting the (new at the time) Zaurus SL-5500 for software development purposes. The first official 3D product was a mobile phone so it made sense to use a portable platform for dev work.
I developed a simple user guided stereo photography application that used the CF camera module for grabbing photos. The camera module produced reasonable quality images for the time and the API was quite simple. The user takes a photo, the application finds the edges in a small window, displays the edges in a small box overlaid over the live view and shifted to the left. The user then manually moves the camera and lines up the edges before taking the second image. There is also some correction applied to the second image to align the images vertically.
Later my colleagues researching display optics used the Zaurus SL-C700 as a platform for testing interesting display configurations. If I recall correctly they liked the C700 because the Continuous Grain Silicon display was clearly specified or maybe it was because the development kits for mobile LCD were in short supply. One such experiment had a SL-C700 with a 3D display that would work in both portrait and landscape orientations. I wrote a simple program to switch between two stereo image files, each processed for one orientation.
Although I worked for Sharp, I did not know anything about product planning for Zaurus. There was one occasion when I was in Nara and saw the C750 and C760 before they were announced. I crossed my fingers for a 3D Zaurus but sadly it was never to be.
Myself, I ended up getting a SL-C750 for personal use and later a SL-C3200. I have used the C750 a lot but I haven't used the C3200 as much apart from trying some alternative ROMs. This is something I want to change now. The most used applications for me have been PIM (calendar and address book) and language tools (dictionaries and Japanese kanji look up). I implemented some applications that I wanted to use, modified some pre-existing tools and built up to date libraries. In the future I plan to use it for editing and developing HTML, scripts and code on the C3200.