Theres not really much can go wrong with an A12k since all the chips are soldered. Take out any expansion cards and just put the A1200 in a nice big box (plenty of space) with some polystyrene chips or bubblewrap or scrunched up newspaper or other padding to fill up all the emty space in the box and it should be OK.
Write "FRAGILE" on the box in big letters too. They won't take a blind bit of notice but it'd probably make you feel better.
