ive heard talk that this not a hard thing to do. Anyone here any knowledge or possibly the know how on this? I'd even be up for paying someone to do this for me if I supply the materials.
Xbox One hardware inside original Xbox controller?
I haven't attempted this so I can't provide you with specific instructions but swapping the shells doesn't seem like too difficult of a task. You may have to do some cutting/gluing but overall I think it could work. As for the thumbsticks, I have no idea how that would work. You should contact a controller shop and ask somebody who works daily with Xbox controllers, they'd know a hell of a lot more than I would.
Good luck.