This potential next project is titled Brooklyn Loves Michael Jackson and according to Showbiz 411, Lee has already cast Samuel L. Jackson, John Turturro, Julianne Moore and Rosie Perez. Also, Anthony Mackie and Kerry Washington are reportedly in talks to join the ensemble. There's word out that the script has a Do the Right Thing connection, but the listed actors don't appear to be reprising their roles from that 21-year-old classic, and this isn't being labeled a sequel.
The Playlist actually shared a pretty detailed synopsis for Brooklyn Loves Michael Jackson, but they were instructed by lawyers to remove the information, so I'll avoid discussing the plot (a quick search for the info will get you contraband spoilers if you must have them). All I will say is that the film's title is the same as an MJ birthday event Lee held last summer paying tribute the late performer. And it primarily deals with the gentrification of the titular borough. Brooklyn Loves Michael Jackson would not be Lee's first work to involve the King of Pop. He directed Jackson in two different music videos for the song "They Don't Care About Us" and he made a video for the posthumous single "This Is It" (for Lee's initial response to MJ's death, read this interview with Time and watch this interview with Katie Couric).
First, I'm glad Inside Man 2 appears to be dead, as the reasoning for a follow-up seemed geared to the superficial plot elements of the original. Yet Inside Man isn't so much about a bank robbery as it's about the racial climate of NYC and America following 9/11, as well as the theme of things not being what they appear. Lee is great at this kind of portrayal of cultural atmosphere -- the post-9/11 cloud also hangs over 25th Hour -- and tackling both the death of MJ and the overall transformation of Brooklyn in the last 20 years (as well as some discussion of race following the election of a black president, no doubt) seem perfectly suited for the filmmaker to use as the backdrop for another essential representation of his hometown.
Other possible futures for the filmmaker involve another go at the African American experience of WWII, following Miracle at St. Anna with an adaptation of Now the Hell Will Start, and another non-fiction look at the Hurricane Katrina disaster with a sequel to his documentary When the Levees Broke.