There are three well known NIT projection sites that I'm aware of: DRatings.com, Big Apple Buckets, and The Bracket Project (which also does the Bracket Matrix). DRatings uses a statistical model, while BAB and TBP use more of a resume kind of basis.
At the time of each site's last update, all of them still had the Vanderbilt Commodores in the NCAA Tournament. If the 'Dores don't make the Big Dance, then I would guess they'll be in line for a 1-seed. As for everyone else, here is the situation right now:
|Team||DRatings.com||Big Apple Buckets||Bracket Project||Average|
NIT seeding goes up to eight, so it's looking pretty firm that the SEC will get four teams in the bracket—and five if Vandy doesn't make the Big Dance. I'm not sure why the Alabama Crimson Tide isn't in the DRatings bracket, but the other two like Bama more than they do the Ole Miss Rebels.
The Florida Gators will probably get one of the top couple seeds. The Georgia Bulldogs are looking at the 3-seed or 4-seed line. The LSU Tigers will inhabit the middle, while Ole Miss will be in the bottom half but not the absolute bottom. If Alabama gets in, they're in the same kind of situation as the Rebels.
With South Carolina not getting in March Madness, consider the Gamecocks a top contender for a 1-seed. Also, LSU has decided not to participate in any postseason tournaments.