The lineup is usually announced around the end of the 1st or 2nd week of January.
As for your hopes/guesses:
- Adele has announced a UK Arena Tour starting in February of 2012
- Kid Cudi seems unlikely due to his current rock band project, unless he ends up performing with them here.
- LMFAO is touring overseas during the months for Mardi Gras
- David Guetta was just in Tampa last night and will be in Europe from March - April.
- Maroon 5 will most likely not be touring during the Mardi Gras dates due to tapings for The Voice.
Sorry to be a joy kill.