Have you looked at the book "Growing Tasty Tropical Plants"? They cover both cacao and coffee - their processing is a little bush league, but it was a fun book, and got me started. (They either don't cover tea, or give bad advice, I don't recall - until a few years ago, most english language sources gave horrible advice when it came to processing tea, and I had to go to Chinese sources to figure it out. (And now, of course, there are english sources available - not as good, but considering how much work it took me to get through the Chinese...)

BTW, I don't know if you're a tea person, but tea isn't that hard - heck, you can grow it outdoors year 'round near Seattle, and in other parts of the country. And it's *tea*. It might be worth it for the trade value if nothing else.