I just got done finishing mine. I think it's pretty much the same thing that you're talking about. I put up a quickee page for you to see. (I'll do up a full site sometime in the coming weeks and submit it BYOAC - I've gotta clean up the panels a little.)
http://www.beerisgoodfood.com/mame.htmI'm running 2 trackballs & 2 spinners via an Optipac.
4 Joysticks via an Ipac4. (The sticks on the end are T-sticks that you can reach though a hole cut on the bottom of the panel to flip them to 4way)
There's a coin button and player 1 start on the left and a P2 coin + start on the right. On the long side the 2 Happ supers have 6 buttons a piece. On games that are 4 player, 2 of the buttons out of the six function as a coin and p3 start and p4 start. Each 4 player game is configured differently. I changed the mappings for games such as Gauntlet so that the sticks go P1 (left end) P3 + P4 on the horizontal, then P2 on the opposite end of the machine. I changed the directional mapping for the sticks on the ends to move the characters relative to the view from each side.
I mapped the controls for player 1 to the stick on the left (end) and the left stick on the long side. and the P2 stick on the right side to stick on the right side of the long end... (got it? I'm not sure if I'm making any sense.)
I'm running Advance MAME along with Advance Menu for the front end. Games are set up to rotate accordingly. Some horizontal games are set to flip vertical though so I can play them with a trackball.
If I babbled incoherently, just let me know...
Smack
redpinata@charter.net
I'll clear it up when I get my site done.