I was intrigued when you wrote "arcade pad," but I think many in the gaming community associate "pad" with a flatter controller (think Sega Saturn's pad), so I'd use "arcade stick" to describe what you're interested in!
That said, I'd recommend Sanwa wholeheartedly. I have a Hori RAP V3-SA and I love it. (dem clicky Sanwa)
If you want to build it yourself, check out akihabarashop.jp. I got my Sanwa buttons from there, and they even have the rarer OBSF-30RG (longer push button for longer life).
I think you'd want to get a JLF-TP-8YT stick, which I believe are the de facto sticks, but you may be able to swap it out later, and also put a restrictor plate or remove it.
Now, if you really want to customize and have someone else do it, not to mention save up, B15 SDM Designs is the king of custom arcade sticks. He's based in England (I think?) but I've been drooling and lusting over his work for years now.