I found their website on the Internet. They are in Denver. Thet moved there from Aspen a few years ago. They are still in business because they had a message about the 2020 holiday season on the website. They also invited people to drop in if they were in Denver. I hope that helps.
Just looked up this jeweler that may carry his designs. If they are still in business, they may know if Sebastian Barier settings are still available. My understanding was that the setting is constructed in France, so the process takes a while. There was a Pricescoper about 10 years ago that got one of his settings done through 66Mint.
-- Sebastien Barier closed, in 2016, the jewelry fabrication business for which he had become known. He's with BaQless in Switzerland (which he helped launch) & is its CEO/President. BaQless is a cufflink-style of post for earrings, so a very different sort of enterprise for him now: