Here's some interesting info:

Wilbur and Peter's merged in '02 - Peter's became Nestle's Chocolate
Company in 1951.

Cargill owns Wilbur - which makes no dark chocolate.

Jacques Torres is a bean-to-bar chocolatier in New York, but sells
mostly chocolates and apparently does not target the dark-chocolate
crowd.

World's Finest is in Chicago and is bean-to-bar. Because their market
is in fundraising, they sell no dark chocolate either.

Blommer is bean-to-bar, based in Chicago and having 3 factories across
the U.S. I think they sell only couverture to candymakers, so you can't
buy their chocolate too easily.

Original Hawaiian Chocolate Factory is in Kona and they do grow their
own cacao trees - so I believe they are indeed the only commercial U.S.
cacao tree grower. I am curious what their chocolate is like; if it is
anything like the Hawaiian Host chocolate-covered macadamia nuts, forget
it. I learned when living in Ghana that the chocolate sold in tropical
locations is made so it won't melt in the heat...which means it won't
melt in your mouth either. Jamieson's is an example - though a decent
chocolate, theirs doesn't melt as easily (and is made in Ghana).

Merckens and Van Leer are bean-to-bar but are also in the couverture
business, not retail.

Geoff