The final feature listed in this article has been added to the extension: the ability to set a custom keyboard shortcut. If you want to switch from using the default cmd/ctrl + shift + A to something else, here's how you can do that:

Go to the Chrome menu > More Tools > Extensions and check the "Keyboard shortcuts" link at the bottom. Find WordPress Admin Switcher on the list click the field next to "Switch to/from admin". Enter your own custom keyboard shortcut.