I haven't shown dressage in a while, but people certainly had setups when I did and I know from looking at their photos on FB that the trainer I showed with still does. My advice to the OP would be to go to a few multi-day dressage shows and talk to people. There's one at Showpark(?) this weekend, then LAEC soon (check the Cornerstone website), Del Mar and Flintridge next month, etc. Here's the calendar from the CDS website: http://www.california-dressage.org/html/calendar.htm
There isn't nearly as much standing around because you know exactly when you're going to ride. You warm up, go in, do your ride, and go back to the barn. Some horses only do one ride. Even if you do two, it seems that they often schedule it so you have time to go back to the barn between rides. It makes for a much quieter scene in the warmup area and by the back gate.