The inclusion of Stella Veneta on this site is uncomfortably speculative. The famous article in the May 1981 edition of New Cycling lists an Italian brand called 'Marca Stella', which possibly translates as 'Star Brand'. I have asked a couple of knowledgeable Italians about this and both suggested that it probably referred to Stella Veneta, which might translate as 'Star of Veneto'.
Stella Veneto is one of a family of brands that is associated with the Michelin (sometimes called the Michelino) family based in San Vendemiano, Venetto, Italy. The story may go something like this:
It's not inconceivable, coming from this background, that Stella Veneta used derailleurs carrying their own brand. Perhaps this explains the models featured in the May 1981 edition of New Cycling.
A footnote that is often added to this story is that the Michelin family that started the famous French tyre company also originally hailed from the Veneto region of Italy.