[Jeb]

you're right, the steel crank can add cost without much value.
then there're the heads which are generally specific to the 427 to take advantage of the larger bore with larger valves and chambers.

as the 427 is considered to be a revver, it is generally assumed you will spend more on rods and bolts and the crossbolt mains. this may not be true with this crowd.

a dampner specific to the 427 is required if you're doing it right, also harder to find (more expensive).

but you're right, you're paying a lot for cachet.

I agree with Evan, build a FRPP Windsor 427 with 4.125" bores and 4" stroke. this is cheaper still, you can get an aluminum 9.5" Windsor block for the price you'll pay for an NOS FE 427 one. and parts are fresher design and more available.