I've found this forum searching for advice on creating my own xbox360 arcade stick and it's been a great source of information. I've got my hands on a Wii TatsunkoVsCapcom madcatz stick and an old xbox 360 wireless controller. The arcade stick currently has a small board in the corner which houses the Wii Home and turbo buttons and 2 switches, one that switches the stick to either d-pad or left or right analogue sticks. This stick usually has to be plugged into a standard Wii controller to work.
I was originally just going to wire the buttons and joystick directly to the existing xbox board but am now wondering if it would be possible to modify panel too so i could use the turbo and stick selector switches too. Would anyone have an idea about this?