Wow, nice. Do you know how straightforward it is to get it with ZFS?
But on the other hand, if you install 11.0 from installer and chose Auto(ZFS) with EncryptedZFS and MBR(GPT) then you will get a GeliBoot installation. There is no boot pool anymore, instead the early boot stages decrypt the root zpool to load the rest of the boatloader, which then decrypts the pool to load the kernel. With bootloader-selectable boot environments.