Drew Hollis from Alesis presents the Control Hub iOS MIDI interface at Winter NAMM 2013 - see it and other NAMM products at Sweetwater's NAMM Report: http://bit.ly/SW_WinterNAMM13
Connect it to your iOS device using Apple's new Lightning connector, then connect your MIDI controllers with a standard MIDI cable. It's got headphone and stereo 1/4" outputs, plus it's bus powered so you don't need a power supply!
Alesis Control Hub Features:
• Connects to your iOS device, Mac, or PC
• For use with virtually any MIDI gear
• Headphone and stereo 1/4" outputs for playback
• USB or iOS powered, no power supply needed