I have noticed that on my iPod Mini, the backlight can fade its brightness down when turning off. I am not sure whether it is done using a stepping down of brightness using software timers, or a hardware setting, but I would think that it may be possible to add an option to just make the backlights top brightness level a little lower.
Now, if this is possible without any major coding, I am uncertain, but there is extra code in place to take into account hardware that can support fading of the backlight, as there are options to change the timing of it.
This would make it possible to increase battery life, as well as provide a way to dim the light being produced by the device when used in a really dark place and you want to be able to see it without squinting and blocking your eyes.