KP - Yes, there were a number of qualified Republcan women, but McCain needed (or at least thought he needed) to capture the vote of the right-wing-religious-wakkos, and Palin had the credentials to do that.
                   Also, it wasn't only the vote, but the ground forces and the network that could be energized through religious affiliations. His, and Hillary Clinton's biggest problem all along was the huge fund raising advantage that Obama had through internet connections. McCain was looking for something to counteract that as well.