My rudder setup(revel at the artwork) and ingenuity:
1. 2 Wooden Boards suitable to be held up by fishing wire-Your feet will be on these...be creative and think of comfort.
2. Raider Pro K-mart brand Joystick(14.99) with suction cups. Attached to #3 and held up by #4.
3. Plastic sheet along with a base oil..suction cups should stay attached for a long while.
4. Screws/Nails Drilled into the Wall- support the joystick onto the wall(Tight Fit to prevent slippage)
5. Fishing wire or any wire suitable to be your "cables".
6. Fish-eye screws(correct word?) string fishing wire through these and nail/screw into computer desk.
Good luck and results may vary. This design is open for improvising.