What is a Patron Saint?

Now that the saint database has launched, I've encountered people interested in finding what saints are patrons of what things. This led me to start searching on the internet and I found that patrons are not always official. In fact, patronage is almost always determined by what canonists like to call "popular acclamation." That is, people in the Church say something enough that it becomes accepted as correct, even though the Church has made no official statement about it.

So from what I can tell there are three types of patrons:
1.) Unofficial patrons occupations, activities and illnesses
2.) Official patrons of churches and other official organizations
3.) Official patrons proclaimed by the Pope

Lists of Patron Saints
Here's some lists of Patron Saints from Wikipedia:
Patron Saints of Occupations and Activities
Patron Saints of Illnesses and Dangers
Patron Saints of Places
Patronages of Blessed Virgin Mary
And the Catholic Encyclopedia:
"Patron Saints" in Catholic Encyclopedia

So that led me to ask, "Who made Wikipedia the arbiter of truth in Patron Saints?" The answers: nobody. Since patronage is usually done by popular acclamation instead of by the official organs of the magisterium it's anybody's guess. Does Wikipedia get a vote in the whole popular acclamation thing? I don't think so.

Well, are there any official patrons? Yes. For example, every Catholic place (church, monastery, college, etc.) named after a saint automatically gets the saint as an official patron. A few saints are officially proclaimed patrons of particular countries or other entities by the Pope himself. The Catholic Encyclopedia chronicles a few:

• St. Joseph was declared patron of the universal Church by Pius X on 8 December, 1870. Leo XIII during the course of his pontificate announced the following patrons: St. Thomas Aquinas, patron of all universities, colleges, and schools (4 August, 1880); St. Vincent, patron of all charitable societies (1 May, 1885); St. Camillus of Lellis, patron of the sick and of those who attend on them (22 June, 1886); the patronal feast of Our Lady of the Congo to be the Assumption (21 July, 1891); St. Bridget, patroness of Sweden (1 October, 1861); the Holy Family, the model and help of all Christian families (14 June, 1892); St. Peter Claver, special patron of missions to the negroes (1896); St. Paschal Baylon, patron of Eucharistic congresses and all Eucharistic societies (28 November, 1897). On 25 May, 1899, he dedicated the world to the Sacred Heart, as Prince and Lord of all, Catholics and non-Catholics, Christians and non-Christians. Lourdes was dedicated to our Lady of the Rosary (8 September, 1901). Pius X declared St. Francis Xavier patron of the Propagation of the Faith (25 March, 1904).

But you're probably thinking, like I am, ok so where's the real list. I mean, are all patrons of various diseases and occupations just unofficial? Well, let's parse the above list carefully:

Pope-Proclaimed Patron Saints

• St Joseph
  
• St. Thomas Aquinas
• St. Vincent (de Paul?)
• St. Camillus of Lellis
• St. Bridget of Sweden
  
• St. Peter Claver
• St. Paschal Baylon
• St. Francis Xavier

Other Pope-Proclaimed Patronages

• Sacred Heart, as Prince and Lord of all, Catholics and non-Catholics, Christians and non-Christians
• the patronal feast of Our Lady of the Congo to be the Assumption
• Lourdes was dedicated to our Lady of the Rosary

I've been scouring Canon Law and the internet for more information that will hone in on our question, but haven't found much. Let me know if you can find an official list of patron saints. While all the unofficial patronage things are great fun, I want to begin with the official list and then move out in a wider circle, noting the origin (and authority) of each patronage. My gut feeling is that the vast majority of patronages are unofficial and even arbitrary. Let me know what you think.