Thor uses mirrors from Velvac
RV Mirrors | West Coast Mirrors | Heavy Truck Mirrors | Velvac
At least that's what's on mine. Very likely to be on the Ace, although I'm not sure.
I would say this.... if the coach you have in mind is otherwise perfect, and only those couple inches are the show stopper, you might consider getting the coach and replacing the mirrors. You Might even find that velvac has a foldable model that would bolt right up!