At the top, go to Members, then Advanced Search. Toward the bottom "and Number of Posts is greater than", type in 10. In options, "Order by:" choose Posts and Descending order. Click on Submit.
You'll get a list similar to Top 25 Posters, except number stops at 11 posts.

And there are just 604 PetTalkers on the list.

If you're curious, try other combinations and have fun!!