So the first BluRay disc for Bakemonogatari came out this week, and the two episodes on it feature a running commentary by Hitagi and Tsubasa, in character, apparently scripted by Nisioisin.
This is easily the greatest extra I've ever heard of.
Thanks to the favored store, I have now listened to both tracks, and they are everything you could possibly have dreamed of. Hitagi privately making a list of things to discuss with Araragi later, Tsubasa insisting that Araragi actually was helping her plan for the school festival, and both of them pointing out ways in which Araragi has carefully taken advantage of the blocking in a scene to make it look like he's taller than Hitagi. Hitagi also describes the opening fifteen minutes of the second episode in terms of this friend of hers who certainly isn't named Senjogahara Hitagi, and who certainly would not have behaved anything like that if she had been aware it would later be broadcast on national television. She's also convinced the footage of her in junior high was taken by a stalker. They also mercilessly mock Shaft's more surreal moments. "And look, the school was actually a portal to another dimension."