I have a suspicion that font loading isn't enabled for the Zaurus display and maybe for good reason. The display of the clamshell units actually starts it's bitmap in the bottom left of the screen - natural orientation is portrait and there is special handling for the Zaurus to rotate all the fonts for the rasops library to render.
I would take a look a the wscons/rasops and wsfont handling code if I was you.
-Andy