The Olloclip is my favorite accessory for the iPhone - more than any case or adapter. It's a deceptively simple little gadget that slides onto the corner of your phone and allows you to choose between three different lenses for your camera. With it you can make all sorts of images that you wouldn't be able to create with just the phone and an editing app.
But the Olloclip only works on an iPhone without a case. While this isn't a huge deal I have found it to be vexing at times, especially when I'm trying to capture something that my kids are doing. At CES this year they were showing a prototype case to address this issue. The cases have a hinge over the part where the Olloclip attaches to the phone which allows an Olloclip user to quickly put the accessory on and start taking pictures.
More importantly for parents perhaps was another product they were showing - an iPod touch (4th and 5th generation) adapter (also pictured above). I doubt I'd ever buy an Olloclip for my kids, but I can definitely see getting an adapter so they can experiment with mine on their devices as well.
Both products should be available sometime in Q1 of 2013. There has been no price determined as of this time.