FBS has developed a lights interface for the PMDG Boeing 747-400 for FS2004 and FSX, specifically for cockpit builders.
Use it to obtain the status of all lights, from Overhead to CDU panels, through FSUIPC or to drive your lights directly through Phidgets LED64 Advanced boards.
Visit http://www.flyboysshop.com to download a trial copy or to learn more.