i'm staying at a campground in hershey PA, and last night a new sunset trail pulled in. it has a hard expandable rear section on it. i dont see that on any of the floor plans on this web site. has anyone seen this. the trailer looks to be 28'-30' long. the expandable part has the same shape as a trailer with a canvas one. when its open the window that looks out the rear of trailer becomes a skylight and then a new rear window pops up from the bottom.