A close button in the address bar

This extension would gain many points in my view if I didn't have to hunt for the tab in the outliner when I want to save close one. Isn't there a possibility to add a button on the right side of the omni bar, next to the bookmark star, that would do this? A keyboard shortcut for bonus points? 

There's just too much mousing involved right now, and I (and many internetters like myself) really dislike mousing.

Thanks for a great extension, I'm really hoping something like this could be done.