My Dad has just put a listing on ebay for a genuine 1964 Mini Cooper 970S Speedometer which he salvaged from a car a few decades ago. It's been stored away all these years and is still in pretty good condition and seems to work.
Anyway, if you or anyone you know is looking for one then take a look here:
GENUINE SMITHS SPEEDOMETER FOR A 1964 970 cc AUSTIN MORRIS MINI COOPER 'S' | eBay
Cheers,
Craig.