Thats an awesome looking bow. Great tiller, clearly you can make a good bow.
Im still going to say, a board has limits before it can be made into a bow. Backing will let you get away with a lot, but backings are not bullet proof. Even if they were, the bellies can fail in compression from bad grain.
Id like to challenge you to find the worst board you can, and bamboo back it. See what you can make, maybe you will surprise us.