But seriously, while I think Radiohead is unlikely, I wouldn't be surprised. Seth wants something major and exciting, something that gets a lot of attention and people talking. Foo Fighters is far too safe a choice; they've been IMP's go-to band a few times already. And Thievery Corporation is very much a club band. LCDSS is definitely a good choice for myriad reasons. But Radiohead is long overdue to play DC/Baltimore and a 3 or 4 night stand would make up for that, and it's something that Seth could pull off.
Also, Smashing Pumpkins opened the relocated 9:30 and I don't think Seth wants to repeat himself.