I made one and I just sit it on top of my existing ironing board. I can take the big board off and lean it against the wall (or stow it under the bed) when I want to use my ironing board for shirts (rare).
I cut a sheet of 3/4" plywood 16.5" wide by 52" long (long enough for 44" fabric WOF and room to rest my iron). I then covered it with "Bo-Nash Iron Slide 2000" which is a stick-on silver thermal cover. The iron slide is 19" x 59" so I had enough to wrap around my 3/4" plywood and then around to the bottom on all edges. I then stapled it with a gun to secure it (highly suggested .... the reviews for it staying stuck on it's own are not that great). To clean it ... I just wipe it with a damp cloth.
I've had it on my board now for almost 3 years and it's perfect! Fabric slides easily when you want it to, it wipes clean easily, I never need to take it off to wash it like cloth covers, and with stapling it to the bottom edge it has stayed in place quite well.
Amazon and a few others are out of stock ... but I found it here ....
http://www.royalyarns.com/Bo-Nash-Ir...B_p_36298.html