I'm looking for any super slow and low doom bands with atmospheric and/or ethereal female vocals.
Any suggestions?

Acid King. Not sure how 'super' slow or low they are, but they are pretty slow'n'low, hehe.

Love me some Acid King, but don't think that's as slow & low as the OP is looking for.

This

http://www.metal-archives.com/band.php?id=650

is where it's at

i came here to say acid king they are slow and low for sure but not SUPER slow and low.

i basically just said the exact thing as KillingFloor. fuckit

I came here to recommend this.

Asva. Slow drone doom? You got it. Female vocals? Yep. Apparently their drummer also occasionally throws in vocals, but their female lead vocalist handles the grand majority of things.

They definitely have a sort of ethereal air around them, too. Actually, they sound pretty much exactly what you want. Both their albums are worth getting... even if the 71% turns you off the Futurists Against The Ocean album, read the review.

Monarch, though the vocals are far from being "ethereal", but the music fits your description.

Thorr's Hammer should fit the bill. Runhild is pretty awesome--she does both ethereal vocals and growled ones and does them both quite well.

I know Baba Yaga is like a funeral doom band made up of women, see if you can find anything by them.

I just remembered that Baba Yaga reformed into the band Gray, you might want to start there instead. Baba Yaga only has a two song demo from 98 but Gray has an album.

Maybe Bloody Panda?

13, although they have a bit of a crust edge at times.

Awesome band and a good rec.

Jex Thoth

A bit different from the other recommendations, but Skumring are worth a try. Clean female vocals though.

No.

Serpentcult might be worth a try. However, as with the rec above the vocals are clean. And it's basically very heavy trad doom, so not really slow enough I think. It crushes nonetheless.

Dark Castle. This band played a friend of mine's basement and they ended up crashing at my apartment. Really nice people, great live show. Not incredibly slow, but really heavy and atmospheric.

I second this.

And bloody panda