I don't have a modular CP yet (hardwired

- what was I thinking?!?), but I think I'm leaning toward the CAT5 solution for both the encoder and CP sides, then using some female to female connectors to connect them together. Since I have a nearly unlimited supply of free cable and connectors from work, it is certainly cost effective. (Even if I didn't, CAT5 cables are fairly cheap, and I would need only one set of connectors.)
The down side is at only 8 wires per connection, I would need 7 connectors to fully wire my IPAC/4. (8 if you include grounds). I don't think this would be too bad because I will probably not be using all 56 inputs on any of my panels, and I think it might help oganize the wires better (e.g. Player 1 controls on 2 connectors routed down the left side, Player 2 controls on 2 connectors routed down the right side, admin connectors in the center, etc)