Here's a list of special considerations for 4-player builds compiled from other threads.
Anything else that should be included?
* Angled Joysticks = bad (include pic and text)
* P3 and P4 don't need more than 4 buttons for MAME games
* Put coin and start buttons where you don't have to reach across another player to press them
* Some games assign credits based on the coin slot used so you'll want a coin button for each player.
* Put Exit, Pause, and other admin buttons where you won't accidently hit them while coining up/start during spirited play
* If you want to play 2-player games with 2 sticks per player (like
Karate Champ Player vs Player,
Smash TV, or
Total Carnage), you'll want the P3/P1 and P2/P4 joysticks to be close to the same reach distance from the player (find pic of gauntlet CP for negative example)
* The position of the buttons for P3 and P4 can cause them to turn closer to or further away from the player next to them.
* Make a test panel and have 4 large players test for elbow room
* How do you plan on moving it? Casters on side for easier transport through a door? flat dolly?
* IPac4 has an overlap between P2 buttons 5-8 (undefined in MAME) and the default P3 joystick directions. You'll want to change those P2 buttons and enter the new settings into MAME.
* Don't drill any holes until you have decided on the art work if any and its position on the CP.
* Most people set up the joysticks/encoder in a 3, 1, 2, 4 configuration so the vast majority of games (1 or 2 player games) have players 1 and 2 in the center.
* For some 4-player games, if you change the in-game control settings so MAME has players in a 1, 2, 3, 4 configuration it will match up with the screen -- farthest left on the control panel = farthest left on the screen. When you choose a playing position on 4 player games like TMNT and The Simpsons, you are mainly choosing a character.
It's not so much that you're player 1 or 2, but you are Marge or Homer.
* One downside to remapping is possibly causing confusion if you have labels/start buttons with the player# imprint instead of a generic "start" label/vinyl button sticker.
* List of 4P games where player #s/characters are in a 1, 2, 3, 4 (left to right) configuration -- compiled by BadMouth
Bomber Man World
Brute Force
Captain America and the Avengers
The Combatribes
Crime Fighters
D.D. Crew
Dark Adventure
Desert Assault
Double Dragon 3
Escape Kids
Exvania
Gauntlet
Gauntlet II
Gauntlet Dark Legacy
Gauntlet Legends
Growl
Heated Barrel
Main Event
Mercs
Metamorphic Force
Numan Athletics
Punk Shot
Quartet
Rampage
Rampage: World Tour
The Simpsons
Sunset Riders
Teenage Mutant Ninja Turtles
Teenage Mutant Ninja Turtles - Turtles in Time
Thunder Zone
Vendetta
X-Men 6 player (X-men 4 player allows you to select character independent of player position)