I have a friend I would like to build something for his N scale layout. I want to scratch build it something different. He models in the 60-70's he has space for something medium size. I want to give him a one of a kind structure...
What is the theme of his layout? That could help in coming up with suggestions. By that I mean is it a specific road? A specific part of the country? Southern railroads would have textile mills, none of which I have seen from anyone. Western ATSF would still have Harvey Houses along the routes. Not rail themed, how about a good model of a Stucky's? One came out years ago that could be greatly improved.
If the space doesn't have a spur going to it, I would have something to do with racing. An engine builder, chassis builder, or even a racing team. It could be based on cars, boats, planes...whatever. If it's a somewhat rural setting, it could even be horses !!! For me, it would either be stock cars or sprint cars. That's my idea !!!
To narrow things down, a bit, is this industry going to be served by rail, or just fill space on the layout?