I am using this by Sascha Paulus -
http://www.spaulus.com/2011/04/custombadge-2-0-retina-ready-scalable-light-reflex/?lang=en
Which is a class that you can drop into your project, easy enough to customize for the appearance you are looking for. I had a slight issue with the placement of the number within the red badge so I shifted it slightly. Other than that, all good.