I'm looking for a hard drive encryption solution

Hi all,

I’m looking for a suggestion on a full drive encryption solution my company can purchase for a specific project rollout.  We created an image of Windows Server 2008 which would be installed from scripts upon boot-up.  We want to deploy over 1,000 servers from the image stored on a hard drive, but we want to encrypt each hard drive with a unique decryption key.  The idea is that the 3rd party installers do not have access to sensitive information stored inside the image.  Here is the process we want to follow:

1. Stage the hard drives at corporate
2. Ship the hard drives to a 3rd party installer
3. 3rd party inserts the encrypted hard drives into servers and ship them to over 1,000 branch locations
4. 3rd party techs boot up the servers and they are asked for a decryption key before the image process starts.  Also, a unique sequence number comes up on the screen.
5. 3rd party techs call our corporate and tell the help desk the sequence number
6. Our help desk provide the decryption key, based on the sequence number (via some database).
7. Techs enter the decryption key upon boot-up and then the scripts install the image automatically

Can anyone think of any existing solutions we could use to satisfy our needs?

Your input would be greatly appreciated.

Peter