Hi,
Cool idea! I just wanted to say that if you (or generally anyone) are looking for a Native American bow, and are going to pay money for this, make sure you actually support native crafts-people. I think there was a law passed not too long ago that non-native people do not have the right to sell "Native American crafts" and pass it off as authentic Amer. Indian. Another reason is that Amer. Indian people who do take up craftsmanship rely on this as an supplementary income, and there is much competition from non-native fake craftsmen.
One vendor/ craftspeople on the east coast where I live is the Wandering Bull (wanderingbull.com). They are a father/son run business and are Wampanoag out of Carver, MA. Not sure if they make bows though. If not a Google search should steer you in the right direction. And of course if you are a bit of a craftsman yourself you can always DIY it.