Audiobus: Use your music apps together.
What is Audiobus? — Audiobus is an award-winning music app for iPhone and iPad which lets you use your other music apps together. Chain effects on your favourite synth, run the output of apps or Audio Units into an app like GarageBand or Loopy, or select a different audio interface output for each app. Route MIDI between apps — drive a synth from a MIDI sequencer, or add an arpeggiator to your MIDI keyboard — or sync with your external MIDI gear. And control your entire setup from a MIDI controller.Download on the App Store
Audiobus is the app that makes the rest of your setup better.
optional status bar or battery level
I use loopy in subway station and sometimes i forgat to charge it. When i'm playing i cannot see the statusbar and so battery level. i quit loopy and look battery and then go back. maybe you can add a battery level option or visible statusbar (like chrome, facebook may be not clickable or slideable), it will be very usefull..