Called Windsor Plywood today and the cost for the Bamboo boards are not bad. The 1x4x8' is $24 and the 1x6x8' is $32. If you purchased the 1x6 you could re-saw the board and have a bookmatched pair of cores. By the way they are vertical laminate.

Found Bamboo Finishing Timber at Windsor Plywood. If you search there site you will find the product. it comes in 1"x4"x8' and 1"x6"x8' . I hope this helps.