Why could not the Kingdom of the Two Sicilies be the basis for the Kingdom of Italy? They were the biggest of all, AFAIK. Kingdom of Sardinia was too French oriented, but it was them who unified Italy. I just don't understand.
This is well past my period, unfortunately, so I can't give you a good answer. Thanks for reaching out to me anyway!
I will say that both Sicily and Naples (the two kingdoms united as "Kingdom of the Two Sicilies") had weaker states in the 17th and 18th centuries than did Rome, Florence or Venice to the north. I wouldn't be surprised if that trend continued into the 19th.