They used to be made by a scrapbooking company, I don't remember the name. I thought it was the greatest thing, until I bought one to take to a retreat: It didn't fit over the lip under the table, regardless of the adjustable screws. I gave it away.
Now where they show this at the ironing board, holding Best Press (or a spray bottle or other starch) - that I think is brilliant! I often have a little pile of threads that I'm trimming off, especially when I'm getting a top ready for the LA. And my spray bottle is in the way if I need the whole surface of the ironing board.