Sure, in most cases one game controller (joystick) will pretty well get you by for most games but in my opinion some games are just better played using the hand controllers/paddles (yes, I know, it is hard to believe) while others are just meant to be played using a free floating joystick. The problem with having these options means manually having to swap over the controllers or reconfiguring the joystick modes (free floating verses self centering). After a while this starts to become a pain, especially if you are switching between them regularly.
To find a solution, apart from tracking down the game controllers themselves, all I needed was a 4 way serial switch box and a 9 pin male to 9 pin male cable which I made up. The trackball was easily configured. It just got plugged in on the ADB bus between the keyboard and the mouse.
I am very happy with my solution as I have finally got my game controllers setup the way that I wanted. That is, available at a flick of the switch.
Apple Joystick Model A2M2012 (Self centering)
Apple Joystick Model A2M2002 (Free floating)
Apple Hand Controllers Model A2M2001
4Way 9 pin Serial Switch Box
9 pin male to 9 pin male straight through cable
Kensington Turbo Mouse (Trackball) Version 5.0 Model 64210