An important thing to keep in mind when talking about priestly celibacy is that the question is not “could priests marry” but, rather, “whether married men could be ordained priests.”
For example, among the Eastern Orthodox (and the Eastern Catholic churches), the custom is to ordain non-monastic priests from among married men. It works in much the same way as the permanent diaconate works now in the Western Church: men who are already married may be ordained to the priesthood, but if the priest becomes a widower, he may not remarry (at least, not without first being laicized).
In the East, as in the West, bishops are chosen only from among celibate priests.
So, if the celibacy discipline were to be modified in the Western church, the only workable model would be that of the Eastern churches. There is no way that the Church would ever allow priests to marry after their ordination, while remaining in active ministry. There is simply no precedent in Church history, in any part of the Church, for that.
Since the 1980’s a relatively small number of married Anglican clergy have been ordained to the (Catholic) priesthood. (This was done in order to ease the transition into the Catholic Church for pastoral reasons, as other posters have mentioned.) There is, however, no serious talk of changing the general discipline of the Western church to match the Eastern churches—I think it is unlikely to happen, for a variety of reasons.
(For instance, the married clergy of the Eastern churches presupposes generally a neat division between “monastic clergy” and “married clergy”. In other words, in Eastern dioceses, nearly all of the “diocesan” clergy is married. It would be considered an anomaly to have a large number of celibate “secular” priests.)