I think you can only get 31 (32 if you count the barbs). Open the editor, and set the number of civs on the world size of your choice to 31.
"We have tried spending money. We are spending more than we have ever spent before and it does not work...After eight years of this Administration, we have just as much unemployment as when we started... And an enormous debt to boot!" — Henry Morgenthau, Franklin Delano Roosevelt's Treasury secretary, 1941.