I found this chrome mount from Vizon-X. The mount originally comes with a 17mm chrome ball to accept Garmin units but after consulting Gregg at Vizon he said he could swap out the 17mm ball with a 1" RAM ball. He did point out however that the mount is intended for 1" and 1 1/4" bars (I had it originally fitted to my BMW Montauk Cruiser).
I have removed the original shim (too small) and had a machinist colleague make me a new one from nylon although I'm sure a wrap of inner tube or similar would suffice.
I have no connection with Vizon-X, but found their custom service to be excellent.