I brought up the idea very briefly in class that labor markets can be in equlibrium and we can still have what you would still call "too much" unemployment. Here are a couple of people discussing the idea in more detail.
Dan Keuhn has a series of posts:
A quick argument with someone who thinks wages are too high.
The blog Economic Thought (by way of Keuhn) uses graphs to illustrate the idea.
Finally, there is this:
I'm posting this exchange somewhat reluactantly. I like that its a kind of "debate". However, I think The Slack Wire side of it comes off as kind of hysterical. There is too much good high level stuff in the post though, so just try to ignore the anger.