Malcolm, here's two pictures of an O scale switching layout that a gentleman brought to a local train show in 2003. He never came again. Pity. I found it elegant in it's simplicity. I don't know if it was part of a larger layout or just his way of enjoying the hobby.
But hopefully, this will help give you some idea as it seems similar to what you would like to do.
I believe his sections were 1' wide and 18" wide:
Rusty
