I am using dwm for Windows now: http://www.brain-dump.org/projects/dwm-win32/
Regularly I use it in Linux where I can use mod+I and mod+D to change between vertical and horizontal layouts.
In the Windows version that doesn't work for me, and I can't find any other command for the function. Does anyone know how it can be achieved? It's a great and fast windowManager. ^_^
I came in contact with the developer, and the function wasn't implemented in the windows clone.