Apple TV update lists an as-yet unreleased minor hardware variant, Apple TV 3,2
Looks like the just-released Apple TV software update contains strings referencing Apple TV 3,2, an as-yet unreleased hardware variant of the Apple TV 3,1, or the 3rd generation Apple TV with 1080p support that Apple released last March. The code name, J33I, as opposed to last year's simple J33, also suggest only the most minor of differences.
MacRumors's Erik Silvka suggests the I might stand for "international", and represent a version of the current Apple TV updated for all those new countries that just got iTunes media content. That certainly sounds reasonable.
No word yet on when Apple will launch the update, but it certainly doesn't sound event-worthy all on its own.