At the present time there isn't anything even remotely similar to KCS' New Orleans that could be used to represent it. While some inroads have been made in regards to modeling business cars they remain largely unrepresented because of the nature of the cars being so individualistic. Some roads, like Frisco and Southern Railway, chose to use a specific floorplan on most of their business cars which makes modeling them at least a little easier if you can find sides suitable for them (Southern/Norfolk Southern, yes; Frisco, no) but by and large most are not yet modelable in N-scale unless a person would choose to fabricate sides from sheet styrene, maybe using Kato window inserts for the window frame detail. As it stands right now the best one could hope for for most of the very unique cars that so many roads ran is to find someone who could design etched metal car sides but even this is not easy to do.
