Everyone is speculating about who's going to be at Lollapalooza, beyond the creakily nostalgic selection of headliners--none of whom, save Kings of Leon, has issued a culturally relevant album this side of Y2K. Jim DeRogatis, for instance, says Lou Reed, Andrew Bird, and Neko Case may also be on the bill.
In this spirit, let us use deductive reasoning to ferret out some other likely candidates.
Lollapalooza's contracts with bands usually have a blackout window (supposedly it varies, but 120 days on either side isn't unheard of) to prevent an act from sapping its Lolla draw by playing Chicago right before or right after the festival. With this in mind, all you have to do is scan artists' tour schedules and look for people inexplicably skipping Chicago on U.S. tours between April and July. Also you can look at who's played Pitchfork in the past two years, has a new record coming, and is now probably out of P4K's price range.
Here are my best guesstimates for additions to Lolla '09, using this totally unscientific method.
Girl Talk: Pitchfork may have helped build him, but a P4K headlining set would pay a quarter of what he can command for shows now. Also old news for Pitchfork but a credible commodity for Lolla: Bon Iver, No Age, Peter Bjorn and John (who will be on tour supporting Lolla headliner Depeche Mode anyhow).
Animal Collective, Atmosphere, Bat for Lashes, the Decemberists, and Jason Mraz all skip Chicago on their upcoming tours. Also good bets: Lykke Li plays a one-off date in Milwaukee August 6, and Taylor Swfit is unaccounted for on August 7 but has a Kansas date the following day.
Wild cards: Fall Out Boy, M.I.A. (she's confirmed at Coachella), and PJ Harvey (NY and LA fly dates only). Lil Wayne plays Hoffman Estates April 10, which is 111 days out from the festival, so maybe that's long enough. Sonic Youth were originally slated to do two nights opposite Pitchfork but have since nixed that.