I had the 15" unibody first gen 2.53GHz and it had the flickering backlighting and was wondering if it had the same issue? 1-3 notches on the backlight and it would flicker.
My 17" does not flicker at any brightness. My 15.4" would flicker at low brightness just after coming out of sleep/powering up, for the first few minutes. After it warmed up it would be fine. My 17" doesn't flicker at any point.