Security Basics: Hardware Encryption

[forensics () slickwillies net]

Does anyone know if any devices exist to encrypt entire hard disks and allow the user to set the password for the 
encryption?  I have seen modules that can be plugged into IDE hard drives (and USB external hard drive enclosures) that 
allow for "transparent" hard drive encryption (all data encrypted) but none of them allow the user to set the 
password(key).  They all seem to come with a "preset" key from the manufacturer.  The key is a token device that plugs 
into the enclosure/module.  I am looking for a device that would allow the user to set the token himself.

Thanks,
WILLIE