Sounds interesting. How old is the frame? ... Perhaps searches for "Cyclo-cross" frames and forks would help broaden your options. "SURLY" makes a 1" threadless "Cross-Check" fork which looks pretty nice. It has a traditional sloping fork crown - which would look very good on an older bike... and especially vintage Italian. 300 mm steering tube length. I wonder if this could simply be cut to the needed length and then threaded with a fork threading die?