I just noticed that Hank Mauel is selling sets of koa in the classifieds. I'd bet he's got some really nice wood. Unfortunately, Hank is curtailing his building due to health issues.
Hank built Sarah a guitar with koa that is extraordinary in grain, color and flame. Of course, it sounds and plays great, too. Hank is/was just about the best deal in luthiery - *exceptional* custom guitars at a moderate price - as good as any luthier you can name. He got respiratory problems from wood dust and finish chemicals. Nice guy, too. If any builder is reading this: you can't go wrong.