CX747, it is unlikely that Boeing makes any further version of the 747. Remember a couple of years ago they had thought of the 500 and 600 variants? They stopped the project because they didn't receive any order for them. They figured that there was no point to produce the 747-500 and 600. It is possible, and I strongly beleive, that the 747 production is going to end in a few years. Boeing's best widebody sellers are the 767 and 777.
There is one thing that sure: neither American, nor Delta, nor Continental will ever have 747's again.
MD-11 and Mirage are right, I agree with them when they mention all the Europeans flying twins across the Atlantic. Well let me mention one more, Sabena flies the A330 from Brussels to Boston. Anyway, what I'm saying is that across the Atlantic you will see more twins that quads, from both sides. Even across the Pacific you will see 777's gradually replacing 747's. Why do you think that the FAA has extended the ETOPS rule up to 207 minutes? Yes of course, 747-400's will be around for a long time, but you have to admit that if Boeing decides to stop producing the 747 it would be a wise decision from them. I'm sure that'll happen soon even if Asia recovers from its economic crisis. They are concentrating rather on the 767 and 777, those are the two airplanes that are gonna be successful in the long haul market.
I don't want to make you feel sad, I have nothing against the 747, I do think it's a beautiful bird but the truth is the 767 and 777 will have more success because are more economical to operate. It is to me likely that soon Boeing will take the decision to end the 747 production like like they did with the MD-11.