I haven't seen a DD boat at the Salt Lake boat show in years. When I've asked, the answer has usually been that they bring the boats that they sell a lot of. While the DD boats move quickly, they don't move a lot - at least not in our market.
I did get one response this year that the DD boat had sold just before the show.
Other than that, there were some smaller V-drive boats, but nothing slalom specific.
This is also a year-round problem in that it is hard to test drive a DD boat since most are custom ordered and the new owners don't want other people to play with their new toy before they do. So, we pay big money for a boat based solely on recommendations, not actual experience.