Being a miniature it is a lot easier and cheaper to use rare woods. Total bow is only 24" nock to nock. I could imagine what a piece of Satinwood to back a full size bow would cost it is mainly used as veneer in expensive furniture
I have another miniature in the works (getting glued up now) with a Ebony belly, Satine (bloodwood) core, and Ebony back. Doubt I could afford that full size if I could even find a 72" ebony stave
But I get it from SH Goode who supplies just about any wood in sizes to up to 1/2 by 1/2 by 2' long. I get my lemonwood and yew from him as well and have an order in for some Pernambuco