In reply to Damien Carbery.

I was able to hack $menu via the 'add_menu_classes' filter to change the Comments number link. Unfortunately menu links have a 'display: block' style so the number is pushed onto a new line. You could add a style: '#wp-admin-bar-new-content a { display:inline;}'.
Code: http://pastebin.com/WsGbkrvk
Screenshot: http://imgur.com/mWtYECW