If you can't find what you want you could probably get a longer one, take the mountings off and cut the end of the pole off. I imagine the pole is separate from the mounts. In towel bars that can be done if they are styled right. Sometimes the style prevents this. I did it for my towel bar cause I wanted a 14" bar and couldn't find one I liked so I bought an 18" and took it apart and hack sawed it down to size. Easy peasy.

That's just what I'm going to do, thanks for the suggestion. I'm tired of looking for one. Love your bathroom sink and the way you mounted the faucets, really great.