I remember an Analog "speculative engineering" article from a few decades that pointed out that plain old structural steel, at the appropriate height of the surface of Jupiter would create a surface with "natural" 1g of gravity. For structural reasons, the ring would have to be spun; but, really, it's just a Niven ring but Jovian-scale. (Lest this be too confusing: the direction of "down" in a Niven ring points antisunward; a Jovian ring points down to Jupiter.)

Modulo the launching of material, scientific needs, etc., there no reason it couldn't've been built by Brunel in Victorian times. Well... scale, as well, I suppose.