I understand what you are saying. But I've been looking for an excuse to try it for a while. Electrically speaking, there is no problem. I am sure I could find a place to power the LEDs and probably even use a transistor or something from the backlight signal to allow it to turn on and off, possibly even different brightness levels.
The trouble is, I've never looked at the spot where a backlight is supposed to go. I do not know what to expect as far as how much room I'd have to work with and whether or not the light has to be uniform all the way across like a CCFL would be or could there be small spaces in between the LEDs?