MAMEWorld Forums - EmuChat - Which gamepads work for this specific supergun?

The following supergun says to have standard NeoGeo controller ports:
www.ebay.com/itm/SuperGun-Arcade-JAMMA-PCB-Neo-Geo-PGM-Atomiswave-Capcom-Konami-Sega-/260930363695

So, I'd like to know: If you connect a game with a kick harness to it to use all six buttons of the controller, which controllers actually work with it? Except for custom-made controllers and those huge aracde joysticks that cost over $ 100, which controllers work with that supergun?

Originally, I thought this is the correct controller for my purpose:
www.play3.de/wp-content/uploads/2010/12/snk-neo-geo-controller.jpeg

Until I noticed that it's actually a PlayStation controller.

So, it seems like this is the standard NeoGeo controller:
http://images.wikia.com/egamia/images/a/a4/NeogeoCDcontroller.jpg

But this is not really a six button controller, is it? O.k., technically, it is. But I don't feel like playing "Street Fighter II" with the Start and Select button.
Would they even be mapped correctly? According to their position on the pad, to match the button layout of a "Street Fighter II" arcade machine, Select would have to be light punch and Start would have to be light kick. (C would have to be medium punch, D hard punch, A medium kick and B hard kick.) But I doubt that this is the case here.

So, which gamepads with at least six buttons are out there that can be used with those ports?

Another question:
Which six button gamepads that have another port could be converted to be made compatible with the NeoGeo port?
For example, I heard that Super Nintendo controllers wouldn't be that easy to be converted since each button needs to be on one wire (or something like that) which isn't the case with most gamepads.
So, which gamepads have the "potential" to be converted like this?

Again, I'm not talking about those huge arcade sticks. I'm talking about actually affordable gamepads that you can take in your hand when playing.