I guess I'm too late, but my vote is for the keyboard hack. You have to try the hack at least once. There is nothing more impresive to your friends than to pull open that contol panel and say," Yea, I tore apart a keyboard and to build this." It's very Macguyver'ish.
If the hack doesn't work, you've only lost a few hours of your time, burnt a couple fingers and had an experience that few will share.
I say hack away, this forum is called "Build your own Arcade Controls" not "send I-Pac $60 and have them build your Arcade Controls".

Hack away my brother... Hack away...
