Kayben, the average height of cutting and ironing surfaces is about 35" or the height of your kitchen counters.
Not sure about a folding surface because the padding and covering for the ironing part would buckle when it was laid back up flat at the hinged area. But you could look at some kind of table that has side expansion wings. My kitchen table has those, but of course that wouldn't be tall enough for cutting or ironing, so it would have to be placed on risers or made taller somehow.
If you made a portable ironing surface, perhaps you could just lay that on your kitchen counter. And when you need to cut, lay a cutting board on that same counter. I know it's not in the sewing room, but you have a counter that's the right height there and it wouldn't take up valuable real estate in your sewing room. And you'd be getting a bit more exercise too!! LOL