So ‘object’ is kind of vague for Levitate. Wagons are objects as are Houses. But that seems dangerous to me. I like the 100 pounds a level limit from Ad&d. But I’m curious about the intended amount.
We allowed a single levitate spell to levitate a war galley. But dispel magic turned out to make this a very dangerous proposition, and it also turned out that war galleys were not particularly aerodynamically stable (or at all, really).
But yeah, our interpretation has been ‘an object of any weight’, for better or worse.