I've not found a shortcut key to the command box on Mac (Alt+D does not work). This is no problem as long as I don't use floating windows because I have Better Touch Tool and assigned my own shortcut key (to move my cursor to the right location and triple click). This initial solution, however, doesn't work if I'm in a floating window because the cursor moves relative to the active window.
I then wrote a shortcut to trigger the menu item: Window>Logos Bible Software - layout name. I knew this name would keep changing as I switched layouts so I triggered the position in the menu. I was the fourth item on the Window menu so my target looked like this "Window;(4)". I was dismayed to discover, however, that this position was not static either. If my floating window happened to be named something that came before Logos (alphabetically), then the Logos item (which is the main window) would move down.
I haven't been able to find a way to consistently hit this Moving AND Name-Changing target! 
Any help would be really appreciated!
The solution that I'd prefer is to make the Position of the menu to go to the main window Static, as this would allow us Mac users to use BTT and easily create our own custom keyboard shortcut to the Command Box.