Most corporate laptops support it, IBM/Leonova do.
The problem is how do you know there isn't a master password (for AMI's bios it used to be "AMIBIOS") how do you know their encryption is any good (there was an enterprise tape vendor that advertised DES encryption but actually just XORed the data with your password)
And finally how do you know they haven't done exactly the same trick but replaced your bios with one that includes a keylogger?
And finally how do you know they haven't done exactly the same trick but replaced your bios with one that includes a keylogger?