4p on a 19" screen?
* Start with a list of games that you want this to play, stick with Arcade games because this is an arcade cabinet.
* If lots of 4p games are on that list and you have kids, roomates, or are more popular than your typical middle age nerd then commit to the 4p design, otherwise scrap it.
* Look at actual four player cabinets such as TMNT, Dungeons and Dragons, Golden Axe RODA, Xmen 4p, and design your cab with those in mind
* Consider CRT, but if you must do LCD and you're going to do 4p then you should strongly consider a pedestal design.