All of the how-tos that I've seen to date for using the altboot utility seem to miss a key point, which is how to install an absolutely minimal normal Zaurus installation to run prior to switching to the altboot.
Say, for example, you want to run OZ 3.5.4 on a SL5600, with the file system run from an SD card. It seems to me that what you'd like to do is flash the Zaurus with some very small image that insludes the kernel and just enough functionality to install altboot, copy the CardFS to the SD card, and set it up.
Or maybe another way of asking this is: once I have a fuctioning CardFS installed on my Zaurus, how much of the original file system can I delete to recover the space?