In both my previous ('04) and current ('06) LSes, lower parts of the transmission tunnel pretty much stayed warm, probably because of the proximity of the exhaust system. In neither of them, however, did the drinks in the center console get hot (other than when they got left in the car on a warm day). As a matter of fact, a friend said that stuff in his center console (on an '03, IIRC) used to stay quite cool in the Arizona summer thanks to the fact that the rear cooling vents run beside it.
You might check the air coming out of the rear vents, and see if it's warm; if not, I'd start looking at the heat shielding in the transmission tunnel...