Does anyone know if there is a Cydia tweak for some sort of notification light? I know there isn't a physical LED for it, but maybe something that makes a part of the screen light up and flash at low brightness or along those lines?
Accessibility features will let you make the camera led flash for notifications.
Same here. My old HTC Touch Pro has a button dead center like the iPhone home button. It's got four hidden LEDs around it and it pulses in a clockwise rotation (white light) when there's a notification. Some enterprising hackers even created a hack to modify the LEDS so that it was multicolored.This is one of the things I want on my iphone more than anything, an LED light on top like the blackberries, some android, etc. Different colours for different types of alerts. Really handy at times.