The other possible exemplar could be Vatican City. Which, granted, is more ambitious, though what history shows is that having sympathetic fascists in power in the host country can go a long way.
I think the impetus for Mussolini to sign the Lateran accords was more to show he could solve the question of how the legacy of the Papal states should be handled, and maybe to appease the more conservative parts of Italian society, rather than cede a part of Italy to another state. After all, the Papal States had been around for longer than most of the constituent parts of the Kingdom of Italy and had real claims on territory.
The other possible exemplar could be Vatican City. Which, granted, is more ambitious, though what history shows is that having sympathetic fascists in power in the host country can go a long way.
I think the impetus for Mussolini to sign the Lateran accords was more to show he could solve the question of how the legacy of the Papal states should be handled, and maybe to appease the more conservative parts of Italian society, rather than cede a part of Italy to another state. After all, the Papal States had been around for longer than most of the constituent parts of the Kingdom of Italy and had real claims on territory.