Three years ago, I stumbled on Russ Prince's website:
http://www.russprince.com/cabinet/It was a HUGE jumpstart. I downloaded his cabinet layout, cut the pieces, and had my cabinet assembled in one weekend.
THAT BEING SAID, I'm now on my second cabinet design (it's now what I call a "modified Russ Prince"), and my sixth control panel design. You'll go through all manner of trial-and-error (I think everyone does this), and after a bit you'll find what works for you and what doesn't.
I don't know if everyone bucks the iPac/Keywiz solution at first. It looks like Russ did. I did. He hacked a gamepad, I hacked a keyboard. In any event, my advice to you is drop the $40 on either an iPac or a Keywiz now, save yourself many many hours of frustration. I use a Keywiz, and I couldn't be happier.
Really don't know what else to suggest. You already have a cab, so you're ahead of where I was when I started. Best of luck.
Hopefully, you'll get to spend more time playing games than playing with the cab itself. I can't remember the last time I played a game on the beast... but I tinker with the cabinet at least once a week. :-)
Chemame