Well, drat. I meant to hit this when I was at the Space last night, but I forgot. And work has Amazon blocked – go figure.
According to Google, there’s still a Williams-Sonoma in Dallas, at 8687 N Central Ste C1-504. The website didn’t list anything as a “cake collar”, and the bakeware page on their website wasn’t working. I can’t say if it was their website or the black-out on some things. However, W-S has been a (full-retail) high-end cooking and baking store for forever.