I think I found them.
I was waiting for a response because I was very interested in this. I am using my 2-player xarcade as the basis for a semi modular control panel. I don't want to cut any wires though because at some point I may want to rebuild the original.
Anyway, since no one had responded and I know many of the normal posters here don't like xarcade (and therefore you may not get a response) so I did a quick look on Google and actually found it (I think).
http://www.action-electronics.com/molex.htmlook toward the bottom of the page at: PP-MLXHU05 5 pin
I ordered some so will let you know in a few days if it was correct. It looks right to me though.
I ordered more than I need so if they are correct I'll send them to you for the shipping cost if you want. It turns out all of the money involved is in shipping and buying pins (which you get 100 of per pack). So an extra 10 connectors was almost nothing..
I hope these are right, but if not, it was worth it to satisfy my curiosity.