[palmertech] and [Bibin] have both completed backlight projects for the Game Boy Pocket recently. The most difficult part of the transplant is carefully removing the reflective backing on the LCD. After a thorough cleaning, a diffuser and backlight panel were added. [palmertech] used a backlight salvaged from a DS, while [Bibin] built his own using LEDs. You can see his backlight in the video embedded below. There’s a disassembly video too.