I read your comments on installing raid via partitions rather than disks and was wondering if you thought it could be faster this way in raid 0 ? I thought if you could partition exactly the surface pallet size , you would have a different read arm for each partition, this might gain you a little speed. ( Only for multi pallet HD). I hope your getting a bit further in your zfs implement. If you find anyway to speed up the system using partitions please keep us informed.

Good Luck