Well, off the top of my head: Isaia for: Paul Stuart, Brooks Brothers, Bijan, Gieves and Hawkes, Bruno Piatelli at Barney's, Arnys D'Avenza for Bijan Attolini for Luciano Barbera Brioni for Bijan and Mariano Rubinacci St Andrew's for: Luciano Barbera, Bergdorf Goodman Private Label, Gianfranco Ferre, Stefano Ricci, Ralph Lauren Purple Label, Louis Boston Private Label, Sulka, Paul Stuart, Harrison James Private Label, Wilkes Bashford Private Label. Also, Dario Zafagni is a St. Andrew's label. Belvest for: Mariano Rubinacci, Hermes, Jack Taylor, Davide Cenci, Bruno Piatelli at Barney's, Gieves & Hawkes R. Caruso for: Sulka, Bijan, Tommy Hilfiger Nervesa for: Calvin Klein Black Label, Cifonelli Castangia for: Battistoni, Jay Kos, Bergdorf Goodman Private Label (MTM) Canali for: Lanvin, Faconnable, Gieves & Hawkes Cantarelli for: Faconnable, Bergdorf Goodman Private Label, Ralph Lauren Purple Label, Brooks Brothers Chester Barrie for: Ralph Lauren Purple Label, Huntsman, Turnbull & Asser, and a couple of new lines at Carrol & Company and Saks, can't remember the names at the moment. I'm sure I'm forgetting a couple of dozen other's. A lot of those collaborations are long past and/or short lived. There is a lot of crossover - better to be able to judge a suit on it's own merits, and not have to worry about who made it. If it's nicely made, it's nicely made.