I have almost the same problem just recently. My configuration is a notebook connecting external Maxtor hard drives. In the past there were 2 OneTouch drives connecting by USB, and additional 2 connecting through 1394 (cascading). All were running fine untile I replaced 3 of them with a 1TB OneTouch 4 Plus last week, now with 2 1TB OneTouch 4 Plus connecting through 1394.
I got intermittent system crashes with big blue screens when I transferred data to and between the drives. And when the system could be restarted, the notebook hard disk light was almlost never off, and would result in another crash, if I waited long enough. The last event brought down everything, I got KERNEL_STACK_INPAGE_ERROR, and when I tried to restart the computer, I got UNMOUNTABLE_BOOT_VOLUME.
I really suspect that the 2 external drives were the causes but cannot explain why. They are simply data drives without OS and used for data storage only. But my notebook is dead and cannot boot now, event after I detach the external hard drives.
It's annoying and mysterious. I don't have any clue yet.
Wesley