Here's one at the link, but I believe I just came across another labelled "nearly black..." Standby. Most of them are very, very dark red.

One more: Moor Place
http://dahlias.net/dahwebpg/Gallery/GalleryHtms/Moorplace.htm

Another Aurora's Kiss
http://www.dahlia.org/cgi-bin/guide/dahlia.cgi?AURORA'S+KISS

I think there are more out there.

Here is a link that might be useful: Crossfield Ebony Pompon

it may be Pot Black which is a MB in dark red quite dark and could be considered a "black red"

I have a picture of a mniature ball....dark red known as
"Crimson Royal".