The first generation Campy record front derailleur has a cable stop, but finding one would be difficult and expensive. Many 70s era FD had a cable stop. If you look in that era, you'll find something. Simplex, sure. I'd probably go for an early Suntour for this bike.

Clamp on stop is a possibility. I'd probably avoid it myself, entirely for the aesthetics. Maybe there's a vintage chrome steel one out there. That'd be OK.