Thanks for the input everyone. I will probably try something like TOK mentioned.
TOK - do you have a build thread with this control panel layout?
I don't even remember... This is on my original MAME machine I built in like 2004.
I'm a Defender freak, so after this machine I built a bartop with a dedicated Defender layout, then still went out and bought a real Defender machine.

Here are pics of the panel. I'd put this at about 80% the playability of the real thing, 90%+ with the simple switch to a lower balltop joystick. My gaudy color choice of buttons will be helpful with the explanation!
You can see the reverse button on the side of the stick (I did it on both sides because it also somewhat mimic's a Neo Geo layout), then on the player two side, I'd use the blue for Thrust, yellow for Fire and orange for Smart bomb... The thumb button on the player 2 side could be used as Inviso for Stargate, but its a bit of a reach. I used the red on the main layout of the player 2 side for Hyperspace.