MidJay Pro is the perfect module if you're a minimalist. It has almost every feature a full size arranger kb can offer plus more. It powers any usb contoller, has vocalizer, display texts/pics/videos and it can stand alone as multi-media player, great also for guitarists/accordionist.

I'm using a Korg Micro Key controller keyboard with it and all of these fits on a backpack including mics & cables.