I would like to find the same kind of swivel passenger seat, because my Itasca's coach floor is 3-4 inches higher than it's E450 cab floor. I would even like a passenger swivel seat that could be raised a bit when swiveled so as to put the swiveled passenger seat up higher to almost match the other coach seating heights whenever the cab seat was swiveled to face backwards.
By the way, the reason that coach floors are higher than cab floors is to provide a "basement area" along the outer under-sides of the coach. For example, our Itasca has taller outside storage cabinets for much better storage than Class C rigs with the coach and cab floors being the same height. I consider this a good feature of a Class C, even though it means that the readily available simple passenger seat swivels makes necessary almost a straight-out leg position for the person sitting in the swiveled passenger seat.