Just managed to get iOS 8 bluetooth MIDI working between an iPhone and an iPad. Latency seems quite impressive to me Probably a bit too early for most people to attempt this due to the slightly wacky software setup. Basically once the devices are connected you can use any existing app that supports midi. But to connect them initially you need apps that let you get to the bluetooth midi settings on iOS. I just about managed this using garageband on the iPad which gives you access to the page that sets your device as the master/central device. And mitosynth on the iPhone which lets me setup the iPhone as a discoverable bluetooth midi peripheral. Mitosynth actually allows for either, but it seems to have a bug which means I can't access the bluetooth settings from it on the iPad, only the iPhone. So until I find other apps that support this, or they fix the bug, I can't try connecting 2 iPads, since I don't have an app that lets me set the iPad as a peripheral. Anyway once the above is done, I can then run any other music apps as usual and bluetooth shows up as a midi device in their normal midi config screens.