An oversize 4 player cocktail? Enh. I'll pass. But you guys enjoy! 
That's what I'm building. My reasons aren't for 4-player (its actually a pretty ---smurfy--- way to play 4-player games because the people on the end of the table have a sideways view of the screen), but because it gives you a natural way to play two player horizontal games, as well as vertical games by just sitting in a different spot. It also blends into a room better than an upright.
That said, some games actually work well 4-player. Gauntlet, for example, because you can rotate the up/down/left/right on the table ends to make left go down, right go up, etc ... so the movement on the screen matches the stick movement.
So it entirely depends on what someone wants out of a cab, but IMO there's a reason 4-player cocktail designs are so popular outside the US.