I have often wondered the same thing. On a warranty visit to the Sunline factory, I did see about 5 other fivers there. This was while they were still in production. Here is a odd situation. My F-281SR was advertised as a 2003 model, it was built in early 2002. Some of my documents say 2003, some say it is a 2002 model. If I go to Kelly blue book or another pricing guide, production years of Sunline fivers are only listed as 2003,2004,2005. I have never seen another Sunline fiver at a campground were were visiting, did see one(new, unsold) at a dealer in Manassas couple of years ago. We bought ours at Recreation World RV in Annapolis. When they sold rvs, last I heard they only rent now, they had many Sunline travel trailers but ours was the only fifth wheel of the brand. I think Sunline priced their fivers a bit too high for the existing market at the time, our trailer's MSRP was over $43,000. Quite a bit for a 30 foot single slide trailer.
2003 Sunline F281SR(weekend fun)
2008 F-450 Pick-em-up
2006 Teton Scottsdale(home)(Sold to a young couple in Missouri, they are happy fulltime campers)