The 3-player CP is the easiest. It would have three joysticks and 6 buttons each player (including coin/start). So that's ten inputs per player. I was thinking Happ Super's plus standard Happ buttons, since I already have most of the parts.
Umm. . . is that
4(joystick) + 4(buttons) + 2(coin, start) = 10/player
or 4(joystick) + 6(buttons) = 10/player
or 4(joystick) + 6(buttons) + 2(coin, start) = 12/player?
+1 on the Supers. I modded mine with the
LS-32/Zippyy upgrade switches and someone else modded theirs with Randy's Standard Soft Touch switches (with levers installed by Randy IIRC). Much quieter and softer feel to the stick.
If you aren't planning on changing them from 4 to 8-way and back by flipping the actuator, you may want to look at the Happ Competitions instead.

In the past I've used GGG's interface's, so I want to stick with what I know.
Don't be afraid to try something new. Different companies have carved out their own niche markets for particular applications. Make sure your application fits. I use Randy's and Andy's encoders and the good news is that while those two sometimes argue here in the forums

, their encoders don't argue with each other or Degenatron's AVR in my CP.

I plan to have each interface mounted to the underside of each panel. Meaning, each control panel will need a seperate interface. And I'd like to stick with USB to ensure forward compatibility.
Sounds like a good plan.
I also was planning a seperate "admin" section with 4-5 buttons. So maybe antoher LED Wiz+GP for that, too.
Which buttons do you want on the admin panel?

Do you want the Coin and Start buttons for P1, P2, and P3 on the admin panel?
Do you want to use LED admin buttons with inserts?
The LED Wiz+GP seems like overkill for the admin panel.
You could save quite a bit by using Degenatron's
AVR encoder for your admin panel.
It is a keyboard-type encoder so you won't run into the potential problems with
USB reassigning the gamepad ID.
If the default keymaps don't match your needs, Degenatron can do a custom keymap for you to match your admin panel. (Up to 20 inputs.) Also, the AVR has a 5v output pin you can use to light the buttons. (No fancy flashing patterns, but it works.)
The two interfaces I was considering were the LED Wiz+GP and the GP-Wiz40 MAX. The GP-Wiz40 MAX would probably be ideal for the 3 player CP, since I only need 30 button inputs total (and it supports up to 32). For the 2P, I was thinking two LED Wiz+GP's. I haven't decided if I want to go the light-up button/stick route, but this would leave that option available. And for the classic panel, either controller would do.
The AVR encoder would also work perfectly with your "classic" panel. (
1 Player MAME Mode.)
The down side is not having the option to do the fancy flashy lighting effects that you're already not sure if you want.
Final thoughts:
I assume you plan on enclosing your swappable panels to prevent wiring damage during handling/storage.
Consider having a small lip jutting out on the admin panel. The recessed space underneath will allow room for a USB cable to attach to your removable panels via a USB feedthru.
Remov. Admin Panel/Cab
--------- ------------------------
| |
USB F/T -USB-cable---Hub
| |
--------- |
-----------------------------------
These
USB A-B feedthrus are great. (Same type that Lizard Lick used to sell.) One per removable panel. Encoder plugs in on the inside. USB cable from hub plugs in on the outside, and excess cable fits into the recessed area when the panel is plugged in and latched down. Of course, you could do a
Reverse Cory Bee and change his bartop + pedestal to your panel + cab, respectively. Feet on the panel fit into recesses to keep it from sliding around.
Bonus round: you can now hook the individual panels up to any computer or take them to a friend's place.
Scott