Baal,
I don't know the scale-speed. In normal playtime, I doubt that anyone pays it much attention. However, I will make an inquiry. During Operations sessions when the desire is to run as prototypically as possible, maybe then it is a factor looked at.
For our layout, the intent is to make it conform largely to ~1940-1960-ish scenery and much of the rolling stock, so I'm sure there is no interest in modelling mag-lev. But your idea might become popular once we get room temperature superconductivity.