So sorry to hear about the loss of your dog.

Here are a few sellers, you can usually search by color.

Schreiner's Iris
Sutton's Iris
Cooley's Iris
Iris4U
Napa Country Iris
Blue J Iris
Wild Iris Rows

Here is a link that might be useful: Blue J Iris

Schreiners has a lot of Black Iris. I have both RAVEN GIRLL and HERE COMES THE NIGHT, both black, both that I got from them.

thanks to everyone, on both counts. I appreciate it. I'm sure I'll be able to find what I'm looking for with this help!

I know you can add more irises so here the sources:
Shreiner
lottsiris.com(better price)
http://lottsiris.com/

I bought BLACK SUITED from Wild Iris Rows last year, they recommended it because they said it was a solid black and a vigorous grower, and I can sttest to that, the 2 rhizomes that I got both but out 2-3 new leads before fall. It hasn't flowered (and probably won't until next year) but based on what I saw i recommend it (also i don't water anything and it still did well).