Quantity   Component name
1 × Arduino Mega 2560 I'll need the extra IO pins and the memory.
62 × potmeters linear 10K
60 × push button switches momentary
80 × blue LED no project without blinkenlights!
8 × CD4051 Electronic Components / Misc. Electronic Components
8 × 74HC165 8 channel input shift register
12 × 74HC595 8 channel shift register
1 × LCD screen 20 characters 4 lines with integrated two-wire interface
3 × Midi port 5 pin DIN socket
3 × optocoupler to isolate Midi ports
1 × Acrylic frontplate see-thru or darkblue
1 × Power supply 5VDC 1A ?
60 × 10K Ohm resistors switch pulldown
10 × 100nF capacitors
80 × 330 Ohm resistors LED current limiters