I built this interface back in high school. The actual joystick was lost long ago, but I've ressurected it here.
A standard analog joystick has two potentiometers and a few buttons.
I made a forearm mount for the pots and linked them to a glove with some simple flexible linkage. I used hot glue, leather and carbon fiber rods.
For the palm trigger, I made a plastic base, mounted the buttons and wrapped the thing in leather. The button pc board from the joystick was mounted on the forearm mount.
This thing ruled at Tie Fighter. The joystick could use some smoothing because there is no dampening effect with the design. Otherwise it came out great. I planned to build a second one using steel cable for the linkage but never got around to finishing it.