IMO Donzis are a hard sell. When a Donzi is sitting next to a less expensive boat say Baja for example, it gets tough to sell the Donzi since most prospective buyers don't understasnd the differences, that is except for the large price premium on the Donzi.
Another issue I've heard of goes like this: A Boat dealer on a relativly small lake say Winnipesaukee becomes a Donzi dealer. On lake Winni, Classics and smaller ZX's are popular, but the lake is really too small for say a 33 or 45 footer. Problem is in order to get the Classics and small Zx's, the dealer must sell the big boats that no one on the small lake wants. Add to this that the Dealers must buy the boats from the factory and deal with the sale (or no sale ie depreciation), you can see why some dealers don't want to carry the line.
One last thing to consider is that the difference between list and the actual price you pay can be huge. I've seen a 22 Classic listed for 55-60K and then sell for 45K. If list is 60K and the Blowout price is 50K, it might look good to the unsuspecting buyer, but if the same boat can be had elsewhere for 45K, is it that great of a deal? The buyer really needs to know the market rate and what a good deal is.