I forget where we got them years ago.....just did some searches too with no luck.
They are just heavy canvas
..and grommets, if you can't find them ready made a good canvas
shop can make them for you, and they'll be sized for your boat.
I might also give JSI or Bacon's a call.
I have removed them and went with a crib rail...which also works nicely for keeping soft luggage, coolers, and all that stuff..from sliding around under sail.
I'll try to post a picture....
I tried the lee cloths once, they don't work well IMHO for 180-200 lb men
No great place to attach them on my boat...the grab rail isn't That strong.