When a category acts as a catalogue of things, it would be handy to have a per-category setting which activates the two-column view:
The topic list in the left column can be displayed as it is in the two-column home page layout.
The topic itself in the right column can be displayed just in a regular way.
This is especially useful when the category is designated to work as a catalogue of things, so that you can keep clicking on topic titles in the left column, and explore topic content in the right column.
Just like Total Command (Windows) / Path Finder (mac), or Finder (Mac) with a file list on the left and a preview pan on the right.
All the menu buttons remain the same - i.e. Latest, New, Unread, Top and so on, so that you can manipulate filtering and ordering of the topic list on the left.
If implemented, even more amazing layouts can be achieved by combining with the Topic List Previews plugin (@angus). For example, you can have product details on the left and product topic on the right.