I offer this hard foam needle felting surface that is a full 12X12 inches square.
I use one side for light colored fiber poking and the other side for dark fiber poking. These are the foam pads we use in workshop here at the farm. It isn't fancy, it isn't pretty but it works.
I am told that if you lay a piece of craft felt on the surface it extends the life of your foam. I haven't tried it yet and will let you know when I do.