Rourke 953 would be my first choice. She can claim British, custom and state of the art steel. Probably unheard of in the US.
For Italian, it has to be pegoretti for the finish. Dario has a big following in the US though, so not exactly rare.
Personally, I’d like an English from the US, as I love what he does with steel.
For truly exclusive, Ben can make you something 😉
And forget campag vs. Shimano, that ship sailed years ago, nobody worries about it any more. For a steel bike’ it has to be Etap with no cable bosses whatsover.
EDIT if she really wants British, Baines flying gate, Paris galibier or a curley hetchins would certainly get her noticed back in the US. That was the reason for the designs in the first place! All available as modern reproductions.