I have not built any custom cars...yet

But I was in the garage working and was thinking about the other thread about a 30x40' display area.. you also mentioned being torn between western and modern trains limited by the brass track for the western. Then it hit me. IMO what would be fun and look neat and different is to use both. Divide the area by a steep hill or a mountain with a tunnel connecting the two "times". With the right amount of a tunnel and times right, you could have the western train enter the tunnel (once inside it takes a hard left turn and continues on its track which is running up underneath the hillside landscape.) Now soon as the western one started to enter the tunnel a modern train could be exiting the tunnel following the same track layout as the western side. Thus only showing 1 full train at a time giving the illusion of a time warp tunnel. Then you could have both a western and a modern train! lol Well, this looked good in my head

Anyways I hope it all works out for you for the show.

Jarred