I think that the color of the koa used would be a determining factor. If it is light and fairly uniform in color it could look good. I'm not so sure about a darker, multicolored top. Also, how are you going to apply the sunburst? You can tint the finish coats or hand stain the wood it self. Applying tint to the finish coats is a lot easier to control, hand staining, especially highly figured wood is tricky and hard to undo, but has the potential to really enhance the figure.
Brad