Is there an alternative for Dimmer that runs on iOS7? I would love to have a tweak that is able to get the brightness of the screen below the default minimum.
I couldn't find one, sorry. However, the developer has said that he's going to work on Dimmer for iOS 7, after other projects are done.
In the meantime - have you looked at the f.lux tweak? Granted, it doesn't dim the screen further than the stock settings but it does get rid of the awful blueness of the screen at night that "experts" say is bad for you and your sleep rhythms/patterns.
Here's hoping Dimmer gets updated, soon. I've never thought of it before, but it'd sure be nice[er] at night.
Marilyn