The Beast. Flight of Fear is a LIM-launch steel spaghetti bowl with excellent theming, but does it have a 540° helix that sends your head careening into your father's arm? No!
I've been pondering this for a while: How large could you build a coaster with engineered wood, for example southern yellow pine impregnated with epoxy resin? Perhaps you could combine the design flexibility of steel with the feel of wood.
That's old-school. I love those slow-motion shots where the train looks like a team of synchronized swimmers. That's wild how the cars swing side to side independently of the track.