Is it possible to have folders listed at the top of a lister in detail view, and all the files after that show up as thumbnails? I've mocked up what I'm talking about:
You could do that using Dual Horizontal mode, with the top set to Details and hiding all files, and the bottom set to Thumbnails and hiding all folders.
Hiding all files or folders can be done via Folder > Folder Options.
You'd want to turn on the Format Lock (packlock icon in the status bar) for both sides to prevent them changing formats when you change folders.
You'd also want to turn on Navigation Lock (button two to the right from the Folder menu, by default). Then, if both top and bottom show the same folder, changing folder in one will change to the same folder in the other.
With all that set up, you could save the window into a Layout or Style so that you can re-create all those settings when you need them, without changing your default setup which you'd use the rest of the time.
Of course, you would lose the ability to show a second folder in the same window, since it would be used for this.
And I just realized you can resize the dropdown arrow width in Customize mode! I am blown away by Directory Opus so far. Just to figure out best license option...