I came across this article in the New York Times which discusses the discovery of a rare Cacao bean in Peru. There are three types of Cacao beans: Criollo, Forastero, and Trinitario. Criollo, which many consider the "original" cacao bean, is the most highly prized bean and is grown in many places, though it arguably reaches its peak flavor when grown in Venezuela (in particular, a little plantation village called Chuao). Although Criollo is reputed to make the finest chocolates that tends to be mellower and less bitter than other beans, it is low-yield and disease prone. Forastero, another strain of cacao, and the most commonly grown, is far more robust and yields the most cacao beans out of the major types, but produces a bitterer chocolate than Criollo. Trinitario, the last type of cacao, is a hybrid of Criollo and Forastero, which allegedly blends the robustness of Forastero with the flavors of Criollo. Nevertheless, Trinitario tends to get lumped together with Forastero as an "industrial" chocolate, with Criollo being the cacao bean of choice for most artisinal producers of chocolate.
The recently discovered bean is called Nacional, which is a particular breed of Forastero. Probably the most interesting characteristic of this particular bean is that it is genetically 100% Nacional. In contrast, most Criollo beans, even when labeled Criollo, tend to have some strains of other bean types in their genome (the widespread cross-breeding of cacao have even led some to claim that pure Criollo does not exist anymore).
According to the article, this particular bean produces a mellow, low acid, chocolate that lacks the characteristic bitterness of most Forastero chocolates, but also is far more disease prone than most other Forastero breeds. In many ways, it sounds like a Criollo.
Several chocolatiers produce bars made out of this bean, though only one is named in the article. So check out Moonstruck Chocolatier if you want to try it.