A totally hypothetical question...
Folks, this is just a bit of fantasy fun, so apply your minds openly!!
If Airbus (or Boeing...or even BAe) dug out the original plans for Concorde, and set about updating them with whatever technology is currently available, what would be the result?
Would enhanced engine technology over the Olympus originals allow Concorde 2 to fly any faster, or more economically? Probably most critically, could any powerplant be made to provide similar performance to the original, whilst meeting current noise (excepting sonic boom of course) and emissions legislation?
Would modern materials science provide any benefits over the original materials (if any improvement has been made!).
And how much would such an adventure cost? I am guessing that the development costs, plus the small capacity, plus the small customer base would make this adventure a non-starter anyway, but please speculate to your heart's content!