Well, the marquee paleohacks thread on chocolate is this one:
There are a lot of interesting ideas there. You can also have a look at Melissa's fun "paleo foods" page:
Note the scare quotes in the title: "Evolutionarily Appropriate, 'Paleo' Foods." I think at this point that Melissa would call paleo-ness into question even more than when that page went up, but if you scroll down to chocolate you can get a good general appraisal of the food.
My quick summary of various sources: I'd say: 1. Chocolate is definitely not paleo in the restricted sense in that you have to oxidize it and roast it to eat it. Even cacao nibs have undergone roasting, since you roast the beans to open up the shell to get at the nib. 2. It's definitely not paleo in the wider sense if you are eating it mixed with a lot of sugar, but you are not so ... 3. I think that chocolate is no good for a digestive system, personally. But if you're eating it in moderation and mixed with other foods then this is probably minimized. 4. There are anti-oxidants, but no one really agrees on whether anti-oxidants do any good. (Maybe it's better just to avoid the "oxidants," so to speak.) 5. The fats in chocolate are pretty nice: about 60% saturated and very low in PUFA. I will sometimes have some 90% or 100% chocolate to add a little more fat to a meal.
My favorite 99%/100% brand is Scharffenberger. They call it 99% because there might be some traces of sugar left in the chocolate since it is made with the same machinery they use for their other kinds.
I think 100% chocolate is OK now and then or in small amounts. I just wouldn't make it a staple food. After all it's not meat or a tuber.