If I've learned one thing about the Obama campaign in the last 8 months or so, it's that they have mastered the art of information control.

Simply, they're too smart to toss everyone a giant clue about who Obama's VP is going to be by naming a convention night after said prospective VP. Obama's team has a certain talent for political theater, be it the plans for the Invesco speech or the timing of Edwards endorsement to couterract the WV primary. When they reveal Obama's VP, it'll be to much more fanfare and with much more theater than simply doing something as obvious as the convention night theme name.

This is just another part of the "Hey look over there!" media campaign that the Obama campaign has been pulling on McCain and the media. He's got them running around in circles chasing their tails over all of these prospective VPs, who then summarily fade off the radar again when a new flavor of the week comes up. By keeping this speculation up for as long as possible with as many different choices, he protects from McCain counterprogramming his choice, and also allows for much more discussion and media uproar when he picks a complete dark horse.

Either that, or Obama and the DNC are running a remarkably shoddy vice presidential search, but nothing from either the DNC nor Obama's previous operations would suggest this.