If you want to get an app into the App Store, you can't really use Bluetooth apart from audio and iphone-to-iphone gaming. You have frameworks for those at your disposal, but the actual Bluetooth stack isn't open.
As far as I understand this breakout cable, it should free you up a lot: You can use public frameworks to interface with the dock connector and simply send whatever you want over it to whatever you want on the other end.
As far as I understand this breakout cable, it should free you up a lot: You can use public frameworks to interface with the dock connector and simply send whatever you want over it to whatever you want on the other end.