CCFLs (cold cathode fluorescent lamps) are another part of the "exagerated" specsmanship world of commercial electronics. CCFLs are made at a variety of unknown factories. They are nothing more than minature versions of the fluorescent tubes at your office. CCFLs are rated for "X" amount of surface brightness, at "Y" amount of current, for "Z" amount of hours. Usually, they are getting 50,000 hours (to half brightness), at 5 mA, to create a 500 nit screen. There are no ways to extend the CCFL unless you turn them down. Running a CCFL at less than rated current, the life of the display goes up. Crank the CCFLs past the factory "spec" and the really bright tubes will go dim faster. Consider a CCFL a bucket of photons; it all comes down to how fast (or slow) you empty the bucket.
In short; there is no upgrade and no such animal as extended range CCFLs.