IIRC, 91 Chorus cones are the same as cones used on most front hubs in the Campag range up to the mid-90s and on Chorus hubs all the way until 98.
Have you tried CampyOldy? He has front axle/cone sets for £20 but am not sure which model they are for.
If nothing else comes up, I have an NOS Athena front hub going spare you can have very cheaply.
I also have a 36H 93 Chorus hub in good condition that is built into a wheel at the moment, but which is surplus to requirements.