The Original Hawaiian Chocolate Factory in Kona gives tours as does Tom Sharkey on the Hamakua Coast of the Big Island. His website isn't much but his farm is nice, with vanilla growing up the cacao trees and surrounded by coffee. He also has a vacation rental and does chocolate making classes.
http://www.konasharkscoffee.com/ The Hilo Farmers market usually has cacao pods for sale. A third farm on the Hamakua coast will be offering tours in about another year.MAlie Kai does not own the trees- it is the Waialua Estate on the North Shore of Oahu and is owned by Dole. They do not give regular tours except to large groups.Let me know if I can answer any other questions- I live on the Big Island and have 2 chocolate shops. My production kitchen, Sweet Paradise Chocolatier, is located in Waimea on the Big Island, the main store is in Kailua, Oahu.