I am looking for a black fig that is cold hardy, One that ripens early, before end of September. I will be growing it in container. Zone 7a not 7b.

Me too :) What altitude are you at? That will play into what will ripen well too. I'm finding that the ability to ripen in cool weather might be at least as important as earlieness here near the mile high city. Our night time temps can drop 40 degrees from the days high. Some that I'm trying here that you might consider include: Hardy Chicago and other Mt. Etna figs, Black Bethleham, Marseilles black vs, Ronde de Bordeaux, Genovese Nero. Mine are still small trees, so I can't say for sure how well they will do, but maybe that gives you a list to start with. Cold hardiness varies with those, but I assume that container growing means you would protect them in the winter.

I'm at 6,500 feet here in Los Alamos, NM. I am able to get an early start due to the green house and keep them a bit longer in the fall. I was thinking of getting a black mission but I'm not sure. I just bid on a Dark Portuguese from northeastnewbie that is selling some on ebay. His growing Zone is similar to mine.

Lou, Hardy Chicago would be the one you want. Ripens early, dark fig, tastes great, and cold hardy.

I should also add that it's easy to find and usually cheap.

I do have the Hardy Chicago and it does well. I just was looking for something like the black mission fig that might do well here.

Nero 600m is a fig that is native to high altitudes.

And Nordland

Ronde de Bordeaux and Marseille Black vs. They both taste good and should ripen in your area.

if hardiness is not an issue because the container will be protected during winter, any black common fig that produces a breba crop will work.  don't depend on a main crop if you have a short season. Intermediate (or San Pedro) type figs are also a good choice for short season growers. 

kathleens black could b,hardy for u, is early ripening, delicious and in the Mission family but larger. u mention mission, its the top mission relative for outdoor in zone7a around wash dc.

oh in a container... u might want something more precocious and super productive. others ppl listed sound great.

Also if you have a fig with two crops, pick either the main or the breba don't be greedy for two crops. So with any early main crop varieties pinch of the brebas and start pinch the tips after 4-5 leaves. Also any small main crop should also be removed at the mid to end of July. I am not growing black mission because I was under the impression it needs the late sun to ripen, RDB, Marseille Blk VS, HC,Rouge de Bordeaux, sultane, Negronne(VDB),Noire De Caromb

From my limited experience I would go with RdB, it grows vigorously and likes to put out lots of figs that start to ripen half august and onward depending on how warm it is and how much sun they  get.

RdB´s habit is too big for a pot.
Pastilliere, HC, Marseilles Black, Nero 600m