Quantum Sequencer developer Anthony Saunders released Photon AU. This Audio Unit app lets you record MIDI in your AU host and export the results as a MIDI file. You can also load MIDI files in Photon to play them back with some tweaks. There is a full manual to explain all of the features.
Photon AU iTunes Description:Photon AU - Midi Recorder with Pad playback & Groove
Record your midi performances using this audio unit in your DAW then save/export them as standard midi files via email or directly to other apps.
Load midi files using Airdrop (uses the standalone version) & select your track to import in the AU version.
Up to four pads can be loaded with midi file data & played back with variations in transposition, loudness, tempo, parts defined as start/duration
You can also load a midi file as a Groove file to allow it to replace midi timing or velocity in your recorded/loaded midi file thereby conforming your buffer midi to the groove pattern (eg trancegate effects)
Most controls automated as AU Parameters (quick record, pad controls, pad playback etc)
Full 24 page Manual available here http://amssoftware.org/manual/PhotonManual.pdf
iPhone version coming soon.