You can do the same thing with Keyboard Maestro (and much much more). This is what the finished result looks like.
Click the Applications Shortcuts icon in the left hand column.Click Keyboard Shortcuts in the top pill shaped tab.You can disable shortcuts via Keyboard Shortcuts.
Before browser makers figured out cmd-q was awfully dangerous without at least a prompt that the user really wants to close 60 tabs, I always changed the keyboard shortcut for the Quit command on my main browser.
