You can purchase this as a service, sending your *libreboot* system into us, or you can purchase this when ordering a laptop and we will install OpenBSD.
Instead of encrypted GNU+Linux, we can supply an encrypted OpenBSD installation. OpenBSD is compatible with Libreboot, and vastly more secure in the default installation. The bootloader of OpenBSD will still be unencrypted, because GRUB has no support for reading from encrypted OpenBSD installs so we would chainload the OpenBSD bootloader in GRUB. However, please note that although OpenBSD uses a similar unix-like design to GNU+Linux, it is vastly more difficult to use for the average user and it has less hardware support (less USB devices supported, etc). Not all software available for GNU+Linux will work correctly in OpenBSD. OpenBSD is only recommended if you have experience using it and know that you really want it, and we will only provide the basic install.
More information about OpenBSD can be found here:
NOTE: OpenBSD is NOT endorsed by the Free Software Foundation! The system is actually libre, but non-copyleft and it will fetch non-free firmware from the package repository. However, you can disable this behaviour. OpenBSD, without any non-free software present, has good support for Libreboot laptops.