We had a 1988 29R Pace Arrow (rear bath floorplan) That was in the days before slideouts. Therefore in order to GET to the rear bath, you had an aisle way between twin beds. My opinion-that is why they fell out of favor- customers did not want to sleep alone.
Now that sideouts make queen beds workable, several OEMs have rear bath floorplans and a few, including mine have a half bath (toliet, sink, and vanity) forward, too. We like that because guests can use the forward lavy without having to pass thru our bedroom to use the rear bath (and two areas allows us to get moving quicker in the mornings) ED