If we keep thinking on tine slices of time, even a shoulder surfer attack (with cameras in case of a pass-phrase :)) can be a problem... We are not talking about how to prevent a break during the time when the user is typing the password (torture attack is still a valid one and no technology will ever prevent it). But I like good ideas: once mounted, the password cannot be retrieved as it's stored in the chipset itself... I don't know if the test pins on those processors will make this vulnerable but it worth a try-catch. And if Windows go into sleep/hybernate, you loose the password and have to mount again to restore operation. This is possible as we mount the driver as a removeable media.