Here's the Customline east/west bed. A few other manufacturers do the same thing. The Customline extension is a good idea but not executed very well. It is fabed out of alum tread plate but it is a pretty rough job. I filed and sanded the welds and trimmed a fair bit off the ends as well as rounded them. I then covered it with marine carpet. The extension's legs, which slide into some RHS welded under the trailer top, were also made from alum (obviously) and as such were pretty sloppy in the steel RHS. I packed them with some s/s washers affixed with s/s rivets. It now sits straight and level plus doesn't flop around. The holes cut through the tent wall for the extension's legs were pretty rough also. I think they should have been trimmed as the rest of the Customline tent is faultless.
Now having said all that, I still think it is by far the best option we paid for. Neither my wife, nor I, are laying against canvas. We both have full length side tables to store our books, torches, personal effects etc. Our pillows are about 100mm off the canvas at the end. But best of all, we don't have to climb over each other. The walkup trailers achieve the same thing but were just too long and too expensive.
You will notice the bed base was modified, to my plans, so that both sides of the bed remain fixed whilst lifting the bed base to access the trailer tub. None of the stuff we store down the sides rolls away. The bed base has since been carpeted with marine carpet.
