[namsman]

I have a few answers:

The SP wasn't built "more robust" than a normal 747. They are all built like tanks. The major problem with the 747 in that era was lack of non-stop transpacific range. The solution to the problem was to reduce weight and drag. Hence the shortened fuselage. The lighter landing weight allowed the use of double-slotted rather than triple-slotted flaps. That was a weight saving as well.

A total of 45 SPs were built and about 30 remain in service.

Can't comment on the 747-8 configuration at this point.

[Prophet in the wilderness]

Wasn't the " Father of the 747 " I don't remember his name , but, he is still alive and old, but, he was quoted saying either last year or a few months ago that " the 747-8I " is the plane that the 747 was suppose to be " .