Merccontrol boxes turn up on Ebay now and then. Also the internal parts are still available, like the cam , shift lever, and throttle lever. I bought the parts last summer from an Ebay store, but I can't remember which one.
Most parts are N/L/A from dealers. Take a look at this Link and see if you can find what your looking for. If you cant find them on EBay then id suggest installing a aftermarket control like one of these.
