It is hard to get any 'official' totals of just the diesel pushers, but below in bold is an overview that was written in 1999 about the whole lineup from Gulf Stream. We know that the large majority of total units of all types would be the towables, and of the motorized units the large diesel pushers are again a small fraction, so perhaps 2,500 to 5,000 of the 80,000 units mentioned over the 16 years in the stats below would be all the DP coaches...and I would expect that a very small percentage of those would be the largest tag axle units. The article appeared in Industry Today and the full text is here:
http://industrytoday.com/article/winning-coaches/
Additionally, the very early 2000's may have enjoyed a similar yearly rate, but by 2007 (my own tour Master's year of origin) production was substantially reduced due to the overall economic downturn and of course production of all coaches of this class ceased shortly thereafter.
In just 16 years, Gulf Stream Coach has developed into a Top Five, full-line RV manufacturer, producing Class A and C motor homes, conventional trailers and fifth-wheel trailers, which hitch into the beds of pickup trucks. Luxury van conversions and RV rentals round off the line.
Brand names of the 80,000 Gulf Stream RVs now on the road include Conquest, Innsbruck, Sea Hawk, Tour Master, Friend- ship, Scenic Cruiser, Sun Voyager, Sun Sport and Ultra. Conventional Gulf Stream travel trailers range in length from 18 to 35 feet with numerous slide-out models. Fifth-wheelers run from 23 to 40 feet and have mostly slide-out models. The firm’s Class C mini-motor homes are 20 to 31 feet in length with multiple slide-out models. Class A motor homes come in a wide variety of models on Ford, Workhouse and Spartan chassis and range from 25 to 44 feet with many slide-out models.
Chuck