Hmm, Donkey Kong is vertical though. No joy controls on either end? I think the great advantage of Cocktail cabs (and one reason I ALMOST wish I had done one) is you can have the standard controls on either end, and then rig a 3rd like yours on the side, enabling basically all orientations of games. Where to put a trackball/spinner may be an issue, but I suppose if you forego 2-player flipping, you could make one end have joy, the other trackball/spinner, and then both on the side.
Looks very nice though.