Laurin, I sometimes let Nina cry it out for about 15 min at night when both DH & I are exhausted. I find if I do this, she's much more settled when I do pick her up and she'll have a good feed. I can't see that it'll do much harm if it's only for a couple of minutes. 15 min is max for me. Just shut the door and go have a shower, eat or something.
We've discovered this week that if we put Nina in her swing at night when she's tired and grumpy, she'll fall into a deep asleep and I can then put her in her cot and she'll either sleep through the night or wake 8 or 9 hours later for a feed (depending on what time she goes down). She's also starting to not be as bad at night. Maybe she's starting to grow out of it ... well fingers crossed anyway!!