D.St-Amand has created some very cool looking designs for DIY MIDI controllers and is documenting his designs and work building them on Flickr.
“I think that this is my very best channel layout! No wire, no front panel screw. Only one PCB will be made for the number of channel required, 2, 4 , 6 or 8 channels. Every control are leds illuminated. The enclosure total thickness is ~16 mm !! (knobs not included).
The ledrings use single color leds and when all the leds are turned off, they are white. Buttons use dual color leds that generates 3 colors; red, green and orange.
The encoder ledrings adaptor is made of anodized aluminum.”
Check out the link above to see a more designs and some build pictures for his prototype.