Not done, but for the sake of slot saving I would probably go for a few Tribunal Altars overlapped using square or (to get a conical shape) circular build. That would make it gold, though.
Oh wow yeah, that is brilliant. Costly to make it conical but yeah, smart! I was thinking using alinor building mats, but couldn't imagine them working right.
Give it a go, experiment with the radius, it may save you some gold if you decide to go for that particular piece of furniture. Of the alinor (way cheaper) I would try Alinor Post, Tall Fence and see what I could get with that by adjusting pitch and roll. Prolly far more slots taken, though.