No known source. However, we have a guy nearby that specializes in vintage wheel reconstruction and he owns a spoke making machine. Lilkely he can solve your troubles. However, we would need one from you as a sample to work from. He's a bit of a space cadet bag lady so I would NOT recommend sending anything directly to him. You need a personal hand-carry intermediary. I'd be happy to do that for you if need be.
Otherwise, surely the Italian vintage vendors can help and you should have a list of those.
Patrick Hayes
Fremont CA