I was also wondering if it's at all possible to flash the OpenZaurus ROM without a cf card but with an sd card or throught pc.
The 5500 and 5000D can only be flashed (to OZ) using a CF card; the 5600 (and other machines) can also use an SD card.
You don't need a very large CF card - 16MB is large enough to flash OZ (though not large enough to flash the Sharp ROM due to the extra odds & sods which it flashes - the bootloader and flashing software, etc.).
I'd see if you can get hold of a 32MB card.
Si