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.
Jamstik Studio MIDI Guitar
Coming soon from Jamstik:
Interesting, Fishman hexaphonic MIDI pickup!
Jamorigins Midi Guitar for ios is really really great but this might just have better tracking due to the Fishman pickup and it is really portable as a guitar with the headless design.
If we can get some good acoustic simulators and a Polyphonic pitch shifter in AUv3 + hopefully Blue Cat's Re-Guitar for ios what more could you possibly need as a guitarist on the go?