While I understand the logistical issues of fitting 4 grown men around a cabinet, I don't think the TMNT control panel was all that thin (although I don't know the exact dimensions and I'm going from memory) and the third and forth players where at a bit of an angle thereby increasing the space for the players.
Also, you seem to be talking about commercial arcades - as you mention the Sunset Riders machine - which I assume would be designed to minimise floor space so there is more chance an arcade will install it.
The benefit of building our own cabinets is that we can do things that would not have been appropriate in a commercial design, from making cramped cabinets to save space to the over-sized control panel monstrosities you see around the forum quite regularly. - If you have the money and more importantly the space, you can have a large monitor and an equally large control panel to allow 4 grown men room to breath.
Now, I don't know how old you are but I'm 28 and my childhood arcade game memories are heavily based around the games from the late 80's to mid 90's and one huge aspect of that was 4 player games like TMNT, Dungeons and Dragons, etc. I can assure you that my friends will have no issues cramming around a cabinet to get in on some 4 player action.
Although I have a little issue with you stating your opinions as if they are facts, I do concede that you have more experience than I (I do take your comments on board and they have made me rethink a few things) and I'm not saying you're wrong, I'm just saying that just because your friends don't like rubbing thighs for a bit of 4 player action doesn't mean mine won't!

Having said that, I'm not sure about the 4 player route anyway, I like the idea that someone mentioned on another thread of having a couple of USB ports and some game pads to allow the third and fourth player to join in.
I
do not want a 5 foot wide control panel with everything under the sun hooked up, but I do have a number of games as a priority, they are:
Smash TV
Ikari Warriors
Final Fight
TMNT
Marble Madness
Street Fighter
Fatal Fury
Unfortunately this poses issues as some of my favourite games are the first two and both pose issues, especially when combined with Marble Madness.
I'm toying with the idea of a modular design or just having a replaceable control panel (which my cabint design incorporates anyway for other reasons) so that I can play my favourites and not have a cramped control panel.
I don't have a mock up of my latest ideas yet, but here is an image of my original layout done in SketchUp...
Things to note:
- The squares up and to the right of the buttons are where the SNK Rotaries are to go, but I have finished the SketchUp models of them yet.
- Obviously the middle is the trackball.
- Ignore the lines running from back to front on either side they were initial ideas on where the sides would be, that's probably going to change
- The angled buttons are too close together
- The angled buttons are meant to be a bit more ergonomic
- The buttons have a pinky button instead of a thumb button for SNK games
- This also allows for the 5th, 6th, and pinky button to be remapped and used with the rotary joystick for Ikari warriors etc. - But joystick would be in right hand, button bashing with the left
- Normal Wico 8-way leaf for left joystick was to be used with rotary for dual joy games
Now in light of what you've said (paigeoliver) regarding the mismatching of joysticks for dual stick games, I would have thought it wouldn't be too bad for a game such as Smash TV in which you aren't trying to fully coordinate the joysticks (they are often moving in opposite directions etc.) like you might with other games.
What do you think? - I might add that I haven't played any other dual joystick games and I'm not that fussed if it's a hindrance on them as long as it isn't
too much of a hindrance in Smash TV.
Anyone have any suggestions on the spacing of controls? How much space do you need around the trackball, I don't play Golden Tee but I would play bowling games.