Amedeo who's here on RFF, sells those. I think there's even a classified AD for it here. There are also a couple of other, mostly Chinese, makers.
Personally, if you have the money I'd recommend Amedeos adapters as they are very well made and are going to last you forever. They will also retain their value if you ever decide to be rid of them whereas a lot of Chinese made-adapters basically sell for pennies on the 2nd hand market.