Today the team proudly announced that Apple has approved Audiobus! They're allowed to share real-time audio between apps!
From the Audiobus Tumblr:
This morning, Apple finished reviewing the first version of Audiobus, and it has been approved.
We’ve been working with a small group of third party developers that we already have a close connection with because we want to make sure that those apps can serve as examples for all the other developers (currently more than 400) for how to implement Audiobus.
Once our initial community of developers have finished the Audiobus integration, we’ll be all launching together and opening up the SDK to the public.
Congratulations to Sebastian Dittmann and Michael Tyson! I know this has been a really stressful time for you. It must be a terrible feeling to be working so hard on something; never knowing if your efforts will see the light of day.
Finally after months of speculation and rumors, we can all breathe a sigh of relief! This comes on the day Apple has sent out the iOS6 Gold Master to developers, which still seems to lack an "Inter-app Audio" implementation.