Bumping this old thread to say that the Hensel twins are now 22 and have a reality series called
Abby and Brittany on TLC. I've watched a couple of episodes. The actual content is completely boring (e.g. girls shopping for clothes) but it's fascinating to see how these two operate - speaking the same lines, finishing each other sentences, etc. It's almost as if they have a shared consciousness. Of course they don't, but as identical twins forced to grow up in EXACTLY the same environment, it's about as close as you can come to having the same mental state. Even then, they still have personality differences. You can watch some episodes online at the above link.