Body
1. Wood: very durable and hard. easy to paint and could even be engraved.
2. Plastic: can give great flexablity, easy to carve out holes, but may not have as good a finish as other materials. May also make the piece look cheap.
3. Foam: A soft foam like material can make the controller more user friendly.
4. cardboard: would be easy to make but would be very weak.
Buttons
Wheel
For the wheel we could possibly use an aluminum bar, cut down. This would give it great durability.
other Ideas include bottle caps ( would be the right size ) and Wooden dowels.
Directional buttons
For the directional buttons, wood was the main idea. Since the buttons would be external and not stuck on to the controller, wood seem the most logical answer.