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 StoreAudiobus is the app that makes the rest of your setup better.
Apple Patents OS X iPad Hybrid
"Apple also has several patent-pending inventions on record supporting a hybrid notebook-tablet or a tablet with a smart cover containing a built-in keyboard ... "
"Apple's patent application clearly shows us how OS X is working on a touchscreen that could be used on an iPad or MacBook which opens the door to a hybrid keyboard, touch display device."
I would buy one.