Call me silly but why couldn't someone with either an original or a repro scan the parts in and use an online 3d printer to print out a new stick? There are online 3d printers that can print with a wide variety of materials including metal.
Right now it's not really the same thing. Maybe some time down the track, you will be able to 3D print anything and it will look exactly like the real deal, but not right now. Right now, the best way for quality plastic repros is injection moulding. But to do it, you need to get all the dimensions exact. If there are compound curves you will need it laser scanned. THEN, and this is the hard part, the engineers have to allow for the fact that part will shrink in different ways depending on thickness and length etc, this is all allowed for in the mould.
I should know, I spent some thousands fruitlessly trying to get N64 thumbsticks reproduced. Somewhere in Shenzhen, I own some shiny stainless steel injection moulds for parts that aren't quite right...