OK, i know that Fleet Farm is a regional store, but i this would apply to any home improvement store that sells bamboo. They have a large diameter bamboo about 4" across with wall thicknesses ranging from 1/4" to 1/2" thick depending on the piece. would this bamboo be suitable to cut backing from? seems like there is plenty of meat there to work with and get more than a couple backings. an 8 foot piece was 15 bucks.
4" will work for backing, pick a piece with the most widely spaced nodes.