If you've verified all voltages and fuses, the next step is the backlight itself. It is a fluorescent tube, they do burn out, your average TV will ship from the factory with the brightness on full. The higher the brightness, the hotter the tube runs, the quicker it burns out, the anodes on either end turn black, so the reaction between them and the mercury gas doesn't occur.
I fix TV's as well as laptops, so I simply connect a standard laptop backlight to it if I'm troubleshooting one. If it lights, the original screen backlight is at fault. If it doesn't light and you know the CCFL lamp is good, something else is wrong. If you determine the screen backlight has gone, replacing it can be tricky, as the screen has to come apart, any fingerprints on the layers inside the screen or diffusers and you'll wreck the screen, so if you're not sure, take it to someone who replaces backlights in panels.
Failing that, if you see a replacement screen, and it's worth the cost, replace the screen as a whole, and have the old screen fixed for a spare to keep safe :)
