Korg PlugKEY (simple MIDI-IN and Line OUT via iOS Lightning)
Just stumbled across this...
http://www.korg.com/uk/products/computergear/plugkey/

Looks like a great way to hook up older gear to iPad. Bit of a shame it isn't able to power USB MIDI controllers ![]()

Comments
+1 for the Korg Plugkey
Simple, quick, clean audio, plug and play and works great with older gear: