What about a 1870 POD?
After all the kingdom of italy was at war with the Pope's state, and the king was actively anti-clerical.
I think he would have smiled upon a Reformed Italian Church Anglican-style, with the king (or a patriarch appointed by the king) instead of the pope as an head figure
Dunno, I think by that time it was simply too late for this being an appealing option - an *Italican church would piss off all of the the clergy, the devout and the liberals, while secularisation would at least get the support of the latter.