Update: You may also want to check out the Bundle Copy module. I haven’t tried it yet, so let me know in the comments if it works!
Recently, I read the Stanford Tech Commons article on Cloning a Content Type in D7 at https://techcommons.stanford.edu/topics/drupal-7x/cloning-content-type-d7. It proposes a simple but (mostly) effective way to wind up with cloned content types in Drupal 7. Summarized: