I think the others have covered most of it. Steel is primarily used in commercial construction for fire proofing. It is good for basements and non-load bearing walls. For exterior and load bearing walls, you then have to use steel beams for your structural support. That is where the excess cost over the wood framing comes in. As Jay J said, I've seen mixtures with wood for the structural support but then that defeats the purpose of the steel to start with.
Have a fire in a steel building and it will melt/bend the metal and destroy the temper of the steel where it isn't usuable any more.
Most residential stick builders aren't set up to do steel framing and the commercial builders aren't really set up for home building. If you want a rectangular ranch, then contact a steel building company and put it up and then finish it out like a house. That won't be cheap either as you would probably need 2 contractors.
It's your nickel so bid it our around there and decide. Your local contractors can tell you more than I can. Let us know how the bids come out. Since you are in humid Houston, make sure the steel studs and steel framing has at least a G90 rust coating or better. I'd hate to see your house fall into a pile of rust someday. At least termites won't eat it up.