follower - Please take references of these, MPQ=0:
Joystick switch - ALPS original, premium quality. cheaper ones available upon request :
http://www.seeedstudio.com/depot/alps-skqu-4-direction-joystick-w-switch-p-161.html
128 * 128 panel - I don't run into smaller square ones with available small sample, 1k+ will be enough for customization:
http://www.seeedstudio.com/depot/graphic-lcd-128128-cog-panel-p-162.html (this one is a bit complex through)
HULK - Metals buttons are really awesome... If not for the cost, I would definitely make a monome with the LED ones myself :
http://www.seeedstudio.com/depot/ip65-metal-push-button-momentary-p-159.html
http://www.seeedstudio.com/depot/ip65-metal-push-button-momentary-w-blue-led-p-158.html