Turns out the 3-song South Park/Rock Band freebie to be included with the South Park: Season 11 DVDs won't happen after all. After it was reported on TV Shows on DVD, someone with Comedy Central phoned the writer to say the retailers he had spoken to had given him bad info. There are no Rock Band tracks (awww) but there are promises of other unspecified goodies.
It sounded weird to begin with, as it was Guitar Hero, not Rock Band, as the subject of an entire South Park episode in season 11. But Rock Band is an MTV Game, and Comedy Central is part of Viacom, which also owns MTV. So, maybe someone went rogue, made up some tracks for a competing game because that's what was used in the show, and got shot down. Or, as Xbox 360 Fanboy speculates, retailers said "Rock Band" meaning "Guitar Hero," the same way I still hear old people still say "Sega" when they mean "any console you plug into a TV." (Yes, "Sega." It was in the grocery store about 10 days ago. I know, I know.)
Who knows. Bottom line, you're not getting any South Park Rock Band tracks. Cartman thinks your tears are yummy and sweet.
Important Update About Rock Band Bonus for South Park [TV Shows on DVD, via TV Squad]