jeez, if you're on CM7 you clearly are missing out on half the features!
like said above, you can adjust ALL aspects of brightness levels, thresholds, etc (screen and buttons) in the settings -> CM settings -> display -> automatic backlight -> use custom / edit other levels.
as for LED notifications, that's in CM settings -> interface -> LED notifications. take an hour or so and just explore the CM settings menu. you'll be amazed at what you can do.
Samsung Galaxy S III - CM 10.1 Jelly Bean 4.2.2
ASUS Transformer Infinity TF700T - Jell Bean 4.1.1
Motorola Atrix 4G - CM9 Ice Cream Sandwich 4.0.4