It looks like he simply made the wood for the sanwa box (where the buttons and sticks are) thin enough for Sanwa stuff. It doesn't HAVE to be mounted on metal I didn't think, it's just that the common wood CP's are much to "thick" for a sanwa. I've heard of people just mounting Sanwa stuff right on a sheet of lexan instead of using wood on the top (I don't know about that though, seems kinda flimsy).
Looks like he just routed out the wood around it without making it flimsy, good stuff.
With you permission, used electronics, I know a site that would kill for these boxes, as they are almost the No.1 item in making a custom stick that alot of people can't make (live in apartments, don't have the tools). I don't know if you have posted on there or not, but on the Hardware section on the
www.shoryuken.com boards, 90% of the topics are about custom stick making/buying. There is also a thread with well over 1000 posts called the "Custom Stick" thread(It's a fighting game website with focus on the 2-D fighters, and almost all agree that a stick is the only way to practice at home for tournys in the arcade, so almost everyone wants to/uses one). However, no one sells premade boxes, as most are just hobbists that make a full featured stick, but most people would rather make their own, the only hitch being that they don't have the tools/wood/skills/area to make them.
So go post on there! Or I can let them know about it, and guide them here, it's up to you really. I know they would really be excited.