Qatar has built a church in Doha, which is a precedent, since Muslim thoecracies severely repress non-Islamic religious expression. Via Daniel Pipes:
For some years now, the Vatican has made reciprocity the key to its relations with Muslim-majority states. For example, Cardinal Jean-Louis Tauran, the Vatican equivalent of foreign minister, commented in 2003 that "There are too many majority Muslim countries where non-Muslims are second-class citizens" and pushed for reciprocity: "Just as Muslims can build their houses of prayer anywhere in the world, the faithful of other religions should be able to do so as well."
That sounded good, but does anyone actually expect churches to be built in Saudi Arabia, the country that most severely represses non-Islamic religious expression?
Yes, come the surprise announcements. Archbishop Paul-Mounged El-Hashem, the papal nuncio to Kuwait, Qatar, Bahrain, the United Arab Emirates, and Yemen, says that "Discussions are under way to allow the construction of churches in the kingdom. … There are around three or four million Christians in Saudi Arabia, and we hope they will have churches." Father Federico Lombardi, the pope's spokesman, adds: "If we manage to obtain authorisation for the construction of the first church, it will be an outcome of historic dimensions."
This development comes in the context of (1) the opening on March 14 of Our Lady of the Rosary in Doha, Qatar, making Saudi Arabia now unique in banning churches and overt Christian worship and (2) the move toward establishing diplomatic relations between the Vatian and Riyadh, as symbolized by King Abdullah's first-ever visit by a Saudi monarch to visit the Vatican in November 2007. The Apostolic Vicar for Arabia, Bishop Paul Hinder, finds that the Saudi "climate" has improved since that encounter.
Incidentally, Qatar's deputy prime minister, Abdullah bin Hamad al-Attiyah, directly addressing the topic of reciprocity: "We [Muslims] are enjoying the construction of mosques and Islamic centres in the west, so we must be fair [to Christians]."
Comment: Should even a single church open in Saudi Arabia, no matter how restricted, hidden, and threatened in, it will be truly significant step, a tribute to both the Vatican's new, tougher policy and to King Abdullah's reform efforts.