Very interesting question! Dual citizenship for you and The Vatican sort of exists, no one really lives in The Vatican unless they are clergy or work for the church specifically within their domain. Many workers usually live in Rome.
The Vatican is a Public tourist gathering and huge faith congregation for holy times. There has never been Catholic clergy I have met who have not been there, but just because they are clergy, does not mean they can live their indefinitely without service, most clergy I know that go there stay for several months, but come back home or go to another parish, like a long vacation, and because it can get cramped at various times, the surrounding flats around Rome become accommodating as well.
So I think that if you are a true faithful Roman Catholic, you should be automatically a citizen of The Vatican, however you may not be able to live there as a primary home. If visiting with your parish and clergymen or clergywoman in an organized planned manner, then that could be an exception, but there is a limit to hospitality everywhere.
Here is the Wiki Piece on it that a previous poster gave out:
Citizenship of the Vatican City is granted iure officii, which means it is conferred upon some of those who have been appointed to work in certain capacities at the Vatican, and it is usually revoked upon the termination of their employment. During the period of employment citizenship may also be extended to a Vatican citizen’s spouse (unless the marriage is annulled or dissolved, or if a conjugal separation is decreed) and children (until, if they are capable of working, they turn 25, or in the case of daughters, if they marry).
On loss of Vatican citizenship, anyone who, as judged by Italian law, possesses no other citizenship automatically becomes an Italian citizen.
As of 31 December 2005, there were 558 people with Vatican citizenship, of whom 246 were dual-citizens of other countries.
The 558 were:
Code:
* The Pope;
* 58 cardinals, resident in Rome;
* 293 clergy, members of the Holy See's diplomatic missions;
* 62 other clergy, working in the Vatican;
* 101 members of the Papal Swiss Guard; and
* 43 other lay persons.
Thus, of those holding citizenship, 80% were Roman Catholic clergy, and most of the others were Swiss Guards, for whom being members of the Church is a condition of recruitment. Only for the 43 other lay persons was there no indication of religion.
These figures concern citizenship, not residence. The citizens working in the Holy See’s diplomatic service abroad, the great majority of the cardinals, and a high proportion of the clergy and laity who work in the Vatican, live outside the Vatican. On the other hand, delegations from other Churches and religious organizations are often given hospitality in the Domus Sanctae Marthae and, since a census counts those who are present in a country on a particular date, a Vatican City census would not necessarily find a 100% Catholic population.