On my 19 I'd made a, more flip-out than flip-up, counter extension near the stove. It was a handy place to set cooking stuff without putting it on the bed. Before I sold the trailer I removed it. I thought that sooner or later I'd find a place for it in the 21.
The side of the drawer stack seemed like a good place for a flip-up shelf. The perimeter of the shelf was 1/8" x 1" aluminum which had a vertical support welded to it. The shelf was about 5" too long. I didn't want it to cover the switches and outlets near the wall. So, cut, weld and grind and it was 5" shorter. The 1" width didn't match the 3/4" thick counter tops, well, actually .7630" if we're going to be picky.
So I cut the edging to match and painted it "Expresso" to match #1.
I wanted to be able to sit on the end of the bed and use a laptop so positioning was important. I also wanted to be able to put it up or down while seated there.
An neighbor gave me a MS laptop. It's starting to grow on me certainly fits nicely on the shelf. I might have to start leaving my trusty travelling Panasonic Toughbook at home from now on.
I tried out a stadium seat that I had. At first I almost gave up on that idea because our bed has a thick memory foam topper. It was kind of rolly-polly. But then the foam settled down became quite stable. I like have a back support if I'm going to me sitting on the bed for any length of time.
Glad that I could re-purpose the old shelf.
Ron