The 747 and 737 can be found
http://www.simviation.com/fs2002jets35.htm. It is the special Yananyi Dreaming schemes. For both, you will probably have to mess with the .cfg file, so I will recomend you visit
http://www.projectopensky.com and check out their 747-400 and 737-800 under the Oceania sections. I am not sure if they will function to their full potential as they were both designed for FS2004, but it is worth a shot. As for the 777 search for b772_qfa_jsw.zip over at
http://www.avsim.com. I am sorry if this is not exactly what you are looking for. Please let me know if I can be of any more assistance.