Meet the Zoom LiveTrak L-20R: a rack-mountable digital mixer made with serious musicians in mind. It lets them live mix with their iPad. It comes with 16 mono and 2 stereo channels with XLR & 1/4″ connectivity. It supports 22-track simultaneous recording. This mixer also has a headphone output for sound monitoring.
You can use this digital mixer to record 24bit/96kHz audio to a SD card. The iPad app lets you control your mix, including levels, EQ settings, channel effects, and a whole lot more.[where to get it]