When I was 10 my little brother had a friend called Eric Jensen or Jenson, I can't remember which, I was 10 after all! That's the only person I've met with that last name. I live in northern California, if you're interested. And, I like it. :) It reminds me of Jennifer. I could totally see it becoming the next Madison or Addison.
P.S. We actually have the same last name. Mine is Johansson, which is like the Swedish form of Jensen or Jenson because Johan is the Swedish form of John and Jens is the Danish.