I made myself a board that is 24" x 60" and just put it out and lay it across my work table. I use it alot when I'm ironing long strips of sashing or even yardage.
I made mine with scraps found in the garage: piece of bathroom paneling and duct tape - and then I gathered up some warm & natural batting and the thermal/silver piece of fabric.
Works like a charm and it was quick and easy to make.