Maybe I am just not looking at it correctly, but it looks to me like the machine still has the original panel, and then you bolted the slikstick onto the front of the original panel.
Ah, ok, I see what you saying. The original CP is gone, but that cabinet style has extra side pieces that go along the sides of the original CP. The original CP was metal and when unhinged and allowed to swing down, did not have sides...it was just a single piece of metal that was bent and not boxed in.
I kept those side pieces on because those formed the sides of my storage area. I built a back and then a hinged top for the area. I could've removed them since they are invididual pieces that are only screwed to the cabinet itself. By removing them, then the SlikStik could be flush up to the monitor like a standard cab layout.
The SlikStik is actually sitting on a plywood base I built that extends all the way inside the cabinet. This base is secured by L brackets and also provides support for the TV. This also forms the bottom of the storage area as well.
Check out this pic if you want to see dual control panels :
http://members.aol.com/pileofmonkeycrap/insane-mame.jpg