Thanks Christian?..it has got me thinking. I might change this for ease of use. I might map the black key (unshifted) to ESCAPE, and then map it when ?shifted? to PAUSE. Here is my logic: I have a lot of parties, and a lot of people will be playing the cab, and switching back-and-forth between a lot of different games (meaning, using the ESC key a lot). I don?t want to have to explain to them the method of shifting or pressing two keys to exit out of a game. Since ESC will be used far more than PAUSE, ESC should be the default button press for the black button. If I ever need to use PAUSE, I will know how, and wont need to confuse anyone else 
Personally, I like a dedicated button for Pause, so I don't have to remember a shift combination in the middle of a game. As Brax said, it would be easy to wire another button up. But it's your panel, in the end.
So how much hell will I catch when I tell you that I bought the SlikStik Arcade Cabinet as well?? <snip> Not cheap, but efficient.
Probably a lot of hell, although personally, I think the cabinet is a better deal than their control panels, FWIW.
Does anyone have a ?I (heart) SlikStik? bumpersticker? 
Fat-Johnny
I'm sure Slik-Stik could sell you one for an additional $50 . . . bleh
(Sorry, couldn't resist).