[investigateworld]

If you can help out a non-engineer here, can the 747 frame be tweaked out even more, or will the production line close?

[Prophet in the wilderness]

They ( Boeing ) is working on it.
Believe it or not, but the 747 in it's conception, was born to be stretched, and in recent years, Boeing's engineers accidentally discovered in their research that the 747 airframe design became more structurally more efficient as it got stretched.

[Moose4]

That's the decision Boeing will be making in the next couple of months. The plans for the 747 Advanced apparently involve adding about 11-12 feet to the fuselage in two sections, fitting four of the new advanced engines being built to power the 787 Dreamliner, increased use of composites, and a number of other internal changes. If Boeing decides not to pursue the 747 Advanced, then the 747 line will shut down...they have fewer than 30 747 orders left to fill, mostly for freighters.

}:-)4