Third version of my "two joysticks in one hand" build, allowing you to do 6DOF with addition of a mouse. Mouse handles yaw and pitch (like an FPS, so shooting feels natural), with index finger handling strafe up/down and left/right, and thumb doing roll and throttle. There's a video on Youtube of the first version in action (haven't played much with this joystick yet). One nice thing is that you can handle mapping of the axes on the hardware itself (e.g. changing inverted axis, or sensitivity of axis), as well as fine tune the colours of the grid to line up with what you want in-game.