Auto create node reference in Drupal 7
This is a good example where Rules module can help you. I myself probably just write some custom code, since that's easy for me. But if you don't want to/can't do this, Rules can help you.

You can setup a rule, that is executed when a new user is created that will create a content of the chosen type. With tokens you can populate the values needed.

Using Rules can be a bit complex, but it's very powerful.