i think console emulation is best done with a usb controller, but that's just me.
You can play most everything with 4 8 way sticks (for 4 player and 2x2 8 for double stick side by side) and 6 buttons for at least 2 players if you want to go the 4-P control panel route.
If you have easy access to the inside of the CP 4 to 8 way adjustable are pretty easy to flip while the game is loading, that is my setup. There is also a servo stick that can automatically adjust between 8 and 4 way.
I would try to stay away from a dedicated 4 way, as you already have 4 joysticks on the cp, but that's just MHO. I have found that if you have to have your guests jump around from one way to control something to another, they get confused. Best to just stand there and bang on the buttons in front of you.