Agree, local CL. Every once in awhile you can find one on eBay that slips past most of the hipsters that want to turn them into SS and fixies...
Set a search alert on CL for Bianchi and cross your fingers. The ones that look like what you're describing will likely be 1979-1987 or so. The top one is an '89 btw. I have a '90 with the blue and red Bianchi decals, but it has non metallic paint. Also, the metallic one you listed first is for sale by a member here

Also- listen to T-Mar's advice! It would do you good to see them in person.
Just don't get overly excited and buy one that's too big or something just because it looks pretty. (guilty)

I have an '82 Nuova Racing that sounds like what you're describing:


Here is the paint scheme on the '90, for reference on decals. I don't have photos of mine handy.