My gut is that Airstream probably went through a cost/sales analysis and figured that this model probably doesn't have enough sales to justify the efforts and cost to build this model. A good example is the slide out units that Airstream built for a decade or so. What surprised me was to hear that there were only about 180 or so of these units built in the Classic line over that timeframe. Those of us owning a slide or those who visited the factory during those days of the slides saw a lot of the special effort needed to build one. I'm sure the EB's don't have that level of engineering and construction required that the slides did, but like the slides, if the sales don't justify the special construction that the rear hatch requires, Airstream will put the resources spent on them towards building trailers that are much more universal across the product line. After all in many cases other than the differences in trim and interiors it's a lot more efficient and cost effective to build out all trailer shells alike.
'04 Classic 30' S.O.,'03 GMC Savana 2500,'14 Honda CTX 700