I’m not sure any dressage show will rival that atmosphere, but there are a fair number of options. Adequan Global Dressage Festival runs every other week in January and all of February and March in Wellington, FL. It’s across the street from the big hunter/jumper show (which has much more shopping/dining). 5* week will have the top level of the CDI running in the big stadium at the jumper venue.
Going to World Equestrian Center in Ocala during one of the dressage shows that has a CDI would have vendors/atmosphere. There is also Dressage Finals in November, which has been at the Kentucky Horse Park, but moves to WEC Ohio this year. Lamplight in August hosts the championships for Young Horses and the FEI. That historically has lots of shopping. I don’t know the west coast options. You could always make the trip to Aachen!
ETA: Somehow I forgot Devon in PA. Historic show, very compact with a good number of vendors and a lot of atmosphere. Unlike most other US shows, there are limited open classes running in parallel to the CDI (only young horses and 4th level+) and also a breed show that runs in the days before the performance divisions.