I (we)made my own "big board" type ironing/designing surface. Purchase 24 by 48 inch half-inch plywood,then use a coffee can to trace a rounded curve at each corner and have someone trim the board for you.
Two strips of wood on the underside provide protection from slipping off of your regular, adjustable height ironing board surface. My husband glued the long strips to the underside and then inserted screws just long enough to not go throughto the top pressing surface.
Next create the pad with a single layer each of Insul-Brite and piece of felted wool blanket cut to exact size of the trimmed plywood. Cover with single layer of the silvery, coated material often used for ironing board covers. This material is wrapped around the edges on all four sides and anchored with staples placed on strips of manilla file holders for reinforcement.
Create your own removable, washable heavy duty cover by purchasing cotton duck. Make a rough pattern using the pressing surface plus ease to go around the sides and down and underneath the board. If you
add single fold bias tape for a casing, you can adjust the cover nicely.
I suggest you fold the topper in half crosswise and allow for two areas to be adjustable. If you create two separate casing areas on the circumference, the cover is easier to adjust.
My open casing areas are on the underside near each long strip. Nylon
drape cord slips through the casing easily and is easy to tie.
I estimate that the total cost of my board and removable cover did not exceed thirty dollars.
I use the board surface for cutting fabrics (with appropriate cutting mat), pressing items, designing blocks, etc.
This is my favorite quilting tool next to my sewing machine. Believe me,
I am the gadget queen according to my dear husband!