I'm waiting for my 16gig card to turn up so haven't actually tried using one yet, however.

It's always a long shot.. Have you tried opening a terminal and running the "dmesg" command?

This will show you the kernel message log. After you insert a SD card, some information should appear (try running once before and once about 10 seconds after inserting a card)

I can't recall messages off the top of my head, but post the last 20 or so lines after putting the card in. That will at least tell you if the system is seeing the card, even if it can't use it..

mkdosfs is a console command tool that will create a file system on a device like an SD card.. You'd need to know the correct device, I can't tell you what that would be.. but it should be in the dmesg output..