5. Has anyone made a trackball hack and hooked it up to there ipac .jpac, or minipac before?
I don't think you can hook up a Trackball/Mouse to the IPAC or JPAC (I mean you can hook up the wires to it, but it won't work).
Hooking it up to a MINI-PAC might work but in Andy page, it says to use his special trackball or HAPPS only. It might have something to to do with the Active Hi/Lo (guessing here).
However, you can play trackball games w/your joystick. For example, Centipede is configured a trackball game and if you look at the game War of bugs, its basically the same game but the controls is not analog, its configured an 8-way joystick.
Since I have only one trackball in my CP, I use my joysticks for two player trackball games (Marble Madness, Atari Arcade Classics etc..) and it plays fine when you get use to it.