JAS Design Build specializes in builtins. They've done a few in our house and we are very happy. First discovered them when we were looking at houses in QA. My wife and I were like "who did these amazing builtins?" Keep in mind that their pricing tends to be on the high end and they are booked out for months...
My favorite custom wood worker goes by The Dusty Woodsman. His website has not fully launched yet but you can check out his work and get in touch with him on Facebook, he also has an IG under the same name.