The light in my G15 has recently started to flicker, but the flickering is intermittent. Much of the time it will be solid, but then, particularily around the upper center, it starts flickering. Turning the light off and on often, though not always, stops the flickering.
Hell's Chicken, I have not yet encountered such a problem. How long did you have the keyboard before the issue? Did anything happen to make the light go bad? Are you positive it is not a power issue? Have you recently added a USB device, firewire, anything like this which would change your power situation?