Phoenix was an early front-runner to host the site, but the new Arizona immigration law may well have torpedoed that option. There's also Philadelphia, Pennsylvania the only city seriously touted that's not in the South (though technically, it's not far from the old Mason-Dixon line).
Bids are supposedly due for the Democrats on May 21. Perhaps then we'll know better what their plans are. Then again, former Virginia Gov. Tim Kaine (the DNC chair) says a decision may not be made until the end of this year.
But are convention sites likely to lead to electoral gain? That's the "conventional" wisdom. People will point to the Democrats and their Denver convention, claiming that it contributed to Obama's victory in Colorado. It's likely that the Republicans hoped for something similar in Minnesota when they hosted their 2008 convention in St. Paul.
But my analysis of the last 13 elections shows that it's a little more than a 50-50 bet. Since 1960, Republicans have only won six states where they hosted their convention site (Florida in 1968 and 1972, Michigan in 1980, Texas in 1984, Louisiana in 1988 and Texas in 1992). Democrats have won seven over that time (New Jersey in 1964, New York in 1976 and in 1992, Illinois in 1996, California in 2000, Massachusetts in 2004 and Colorado two years ago).
So don't chalk up Florida to the Republicans in 2012 just because Tampa is hosting their convention. Nor will Democrats necessarily be able to pencil in Missouri, North Carolina or Texas in their win column, just because their city has a convention. But when it comes to Southern conventions, Republicans hold the edge. The Democrats are 0-2 for picking up the state (losing Florida in 1972 and Georgia in 1988). The GOP is 5-0.