I only want it for Invaders, Galaxian, Galaga, etc, so the horizontal stick is fine for me (my current cocktail cabinet is the same).
I spent a long time looking over cabinets before finalising the design. The main reason for the 2 side box design was to make the whole construction easier, but to try and keep a relatively authentic look.
It was based on a combination of a mates Taito's machine (thanks Carl) and this original Aussie cab
http://www.aleax.com/personal/alias/arcade/finished.jpg which has the same two side style box design.