I don't know if this has been done or not,but what would have happened if the pope decided to unite Italy instead of Garibaldi? What would Italian history be like because of this? Which Pope would have the best chance of success?
Best chance for it to happen is if Pius IX decides that liberalism would be a useful tool to improve the Papal standing instead of a threat to Church authority.
And Garibaldi was an unwitting pawn of the Piedmont house - he was reportedly bemused with their decision to give his home city Nice to the French to secure their help in uniting Italy.