I heard something somewhere about hard disks with a layer of thermite inside the platter. Can you say "ferrous vapor"?
For me the ideal cryptosystem would be a small notebook with a thermite hard drive and TEMPEST shielding and no multitasking.
you forgot the auto self destruct if the unit is more then 4 meters from your person.
If we're going to have auto self destruct with a range limit, it should also be waterproof so I can take it swimming (and so that the self destruct system won't be impeded by water). And if it's going to have a four meter limit, it needs to be so light that I can carry it absolutely everywhere, like under 500 grams, and if it's going to be that small, it won't be able to have a keyboard (use pen input) or a hard drive (lots of battery backed ram instead). In fact, now that we've dropped the hard drive and the keyboard, it might as well just be a dedicated crytosystem, make it about 10cmX10cmX1cm and give it an ether port, an rs232 port, a pcmcia port and an rj11 port. It's doable and would provide the ultimate security. e