one thing you need to learn is that arcade controls are not cheap. I have around $500 tied up into my control panel. (2 players, 6 buttons each, trackball), once you factor in the cost of the wood, paint, plexiglass and hardware (hinges, corner braces).
people like to bash the x-arcade stuff, and i'm not sure why. i had an x-arcade 2 player unit for years, and honestly i cannot tell a difference between their pushbuttons, and the happ pushbuttons i have now. if you ditch the trackball, you can save a good bit of money, but dont expect a panel like this to be cheap. also, if you dont have the right power tools, making your own can be difficult and time consuming. to do it right you would need a drill, saw (i used both a jigsaw and a circular saw) and a router, along with various bits which arent exactly cheap. so you may need to factor in the cost of tools.
lots of people buy xarcade controllers and are pretty happy with them. often, after a few years of use however, they seem to end up building thier own anyway.
you can build a contoller much cheaper than i did, but i wouldn't expect for it to end up costing any less than it's xarcade counterpart.