Are you wanting the FPS360 controller to still have the same button remapping functions that it currently has? or just have a 360 controller stuffed in there and the thing setup up in a fixed position?
Stuffing a Wired 360 controller into that shell and setting it up in a fixed layout is easy enough and wouldn't be too difficult.
Stuffing a Wireless controller in there is even doable in a fixed type of layout, a bit more work but also doable for sure.
Keeping it so it has the feature of moving buttons and such around though is a much, much larger project and would require boat loads (like a fleet) of work. I worked on
The CGnome Project and it's the type of thing that would have to be crammed in there as well to still have that kind of button moving option.