I have always thought of M&K as "Comrades-in-Arms". In some ways closer than lovers and in other ways, competitors.
You couldn't say it in better terms.
All this discussion about being lesbians or not reminds me a lot of things about the same discussion with other anime series.
I'm not agree with Alesiopdv, I don't think that is something obvious. To analyse this, you have to keep in mind a lot of things. First, the anime comes from Japan, and japanese people has a very different point of view of several matters. There are a lot of series where western people only see "lesbians" and "yuri" because western people use to see everything in black and white, missing the grey in the middle. So if two girls are close enough, sharing a deep friendship, they have to be lesbians. That's a very poor and inmature way of see the world.
This same discussion is recurrent in Bubblegum Crisis Tokyo 2040 fandom, where thanks to the changes that ADV made in the english script, a lot of people think that Linna and Priss are lebians. They are comrades and partners and Linna has a great devotion for Priss and in some points she feels envy for Priss too. In this same series we have Sylia Stingray who really has some lesbian vibes, but she could be categorized as bisexual. The funny thing is the fandom care about Linna being a lesbian when this observation is out of character and out of the original canon.
With Noir happens something similar. I can accept some lesbian vibes from Chloe and Altena, but this vibes don't mean that they ARE really lesbians. The two of them are characters with a deeper emotional disorder, they can be anything besides lesbians. Chloe is obsesive, she grew up being obsesive with Kirika and living only with Altena in the Manor doesn't help her so much. We can even say that Chloe feels a very deep admiration for Kirika tha could be translate as "love" but not in the most pure sexual way.
I think that in Noir's case and mainly in Mireille and Kirika's terms we are dealing with friendship and partnership as well with a very intrincate relationship since they are in a tension point always. Kirika killed Mireille's parents and Mireille said that she would kill Kirika when everything ends. This is more complex than a lesbian relationship IMO. As I read in other posts in this thread, Mireille isn't a shy girl. If she would want to have something with Kirika she would do it for sure. And the examples Alesiopdv put as prove of their "lesbian relationship" aren't enough. Sleep in the same bed with someone doesn't imply that you have to have sex with that person, just to mention one thing.
About other animes dealing with yuri and shoujo ai, Kannazuki no Miko is one of the best examples. I didn't like Kannazuki, but isn't because of the yuri factor. I didn't like it because the mix of genres this series have. You have mechas, mythological demons, schoolgirls, mikos and yuri. All in a 13 episodes series where anything of those things were develop in a deeper way. The love story was the best and if the series would focuss more in that would be much better.
I agree with that definition because their reltionship was a troublesome and complicated one. We dont know what happen with them afeter the ende, maybe they married and got children.
Hey man, sorry for blow out your baloon, but they maybe get married and have children in their next life. But in this time I doubt it.
So the two shots and the broken watch at the last scene of the last episode, didn't mean anything to you? In this lifetime, the only thing they would share will be a coffin, six feet under earth.
So if you want to see good stories about lesbians, go and watch Utena and Sailor Moon.
In Sailor Moon there is the most beautiful love story between two women with Haruka and Michiru. And don't tell me that is dramatic and blah, because if you are looking for a mature story involving shoujo ai, must be dramatic and epic.