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.
For those of us (or anyone who could benefit) who do our thing - be it music or whatever - on an older iPhone: I wonder if it is possible to manufacture what is basically an outboard touch-screen that you plug in to the iPhone's CCK (or Bluetooth?!?) that will give you a larger screen to manipulate whatever onscreen manipulatin' we need done; perhaps such a gadget is cost-effective and could forestall the need to go after another device that pretty much does everything as the one we're already carrying around. Your thoughts?